Sabar D Hutagalung | Jazan University (original) (raw)

Papers by Sabar D Hutagalung

Proceedings of SPIE, Feb 20, 1998

ABSTRACT Tin selenide (SnSe) thin films have been prepared by encapsulated selenization technique... more ABSTRACT Tin selenide (SnSe) thin films have been prepared by encapsulated selenization technique. The Sn/Se stacked films were deposited by vacuum evaporation and annealed at 200 degrees Celsius for 3 hours to form a stoichiometric SnSe compound. Optical absorption measurements were made on the as- prepared sample using spectrophotometer in the range from UV to visible region (200 - 900 nm). The absorption coefficient, (alpha) was found to be greater than 105 cm-1 that suggested the occurrence of either indirect allowed or direct forbidden optical transition. A further investigations on the (ahv)1/2 and (ahv)2/3 plots against photon energy have been carried out and the resulting optical bandgap obtained from indirect allowed transitions were 0.95 eV for 40.5 nm sample and reduced to 0.79 eV for 125 nm sample thickness. In the case of direct forbidden transition, the energy gaps were between 1.20 - 1.08 nm. The results also showed that the band gap decreased with increasing sample thickness.

Silicon nanowires were synthesized on Si substrates (111) via thermal evaporation using AuPd thin... more Silicon nanowires were synthesized on Si substrates (111) via thermal evaporation using AuPd thin layer catalyst. Pre cleaned of Si wafer was used as a substrate to assemble the nanostructure products. In this work, the effect of growth temperature that ranging from 800 to 1000 o C on the formation of silicon nanowires studied extensively. X-ray diffraction and field emission scanning electron microscope were employed to characterize the structures and morphology of nanowires. Vertical aligned silicon nanowires have been successfully grown on Si substrates at 900 and 1000 o C. At 1100 o C, the high aspect ratio of silicon nanowires can be produced but the formation density is low. The presence of AuPd catalyst on the tip of nanowires, it is expected that VLS is the most suitable to explain the growth mechanism of obtained SiNWs. The crystalline structure of SiNWs was proved by XRD data. ABSTRAK Silikon nanowires disintesiskan pada substrat Si (111) melalui penyejatan terma menggunakan lapisan nipis AuPd pemangkin. Sebelum dibersihkan Si wafer telah digunakan seperti satu substrat bagi memasang nanostructure produk. Dalam kerja ini, kesan pertumbuhan itu suhu yang meletakkan dari 800 hingga 1000 o C pada pembentukan silikon itu nanowires belajar dengan meluas. Belauan sinar-X dan mikroskop elektron penskanan pancaran medan diambil bekerja untuk mencirikan struktur-struktur itu dan morfologi nanowires. Silikon jajar tegak nanowires telah dengan jayanya ditanam atas substrat Si pada 900 dan 1000 o C. Pada 1100 o C, nisbah aspek atasan silikon nanowires akan dapat dikeluarkan tetapi ketumpatan pembentukan adalah rendah. Kehadiran bagi AuPd pemangkin pada hujung nanowires, ia dijangka yang VLS adalah paling sesuai untuk menjelaskan pertumbuhan mekanisme memperolehi SiNWs. Struktur habluran bagi SiNWs adalah terbukti oleh data XRD.

Journal of physics, Apr 15, 2013

This article presents on a simple sub-micron wire fabrication by means of local anodic oxidation ... more This article presents on a simple sub-micron wire fabrication by means of local anodic oxidation atomic force microscopy technique. The silicon-based structure consists of two adjacent terminals serve as probing pads and connected with a wire width less than 200 nm. The pad dimension and wire length are 49 μm2 and 11 μm each, respectively. The fabrication process is conducted at room temperature 24–27 °C with 50–60% relative humidity and operated by commercial atomic force microscopy without any modification done. Furthermore, the local oxidation is performed using gold coated AFM probe tip and assisted by the used of special language supported by the equipment software. In addition, 9.0 V applied voltage with 2 μm / sec writing speed is used to realize the oxidation process. I-V characteristic of bare device shows there is a current flow through the device when a range of voltage is applied. By using this local anodic oxidation technique, the silicon wire-based structure is fabricated and used as gas sensor sensing part. The silicon device demonstrates an increase in resistance as introduced to gas environment. The silicon wire device shows relative sensitivity of 35% to the oxygen gas.

Procedia Manufacturing, 2015

This article presents a fabrication of junctionless sub-micron silicon wire based device by means... more This article presents a fabrication of junctionless sub-micron silicon wire based device by means of atomic force microscope nanolithography for carbon dioxide and nitrous oxide gas detection. The final product was obtained after a sequence step of silicon and silicon dioxide etching process. The device consisted of three parallel sub-micron silicon wires which connected to two adjacent contact pads. The obtained silicon wires width ranging between 233 nm to 340 nm which fabricated under a controlled environment. This experiment utilized the use of silicon-oninsulator wafer as a raw material and atomic force microscope nanolithography as a method to fabricate the device structure. The bare device was electrically characterized using semiconductor parameter analyzer and behaved as a resistor where there was a current flow from one contact point to another contact point. The functionality of the fabricated junctionless device was prolonged by tested the device under gaseous environment at room temperature. The device resistivity was increased upon exposure to both target gases compared with before gas exposure. The response time and recovery time of the device was observed to be less than 1 minute for both target gases. The fabricated junctionless sub-micron silicon device showed higher sensitivity to carbon dioxide gas which calculated to be 138 %.

IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, Dec 1, 2007

This paper presents the effects of calcination time and sintering temperature on the properties o... more This paper presents the effects of calcination time and sintering temperature on the properties of CaCu(3)Ti(4)O(12). Electroceramic material of CaCu(3)Ti(4)O(12) was prepared using a modified mechanical alloying technique that covers several processes, which are preparation of raw material, mixing and ball milling for 5 hours, calcination, pellet forming and, sintering. The objective of this modified technique is to enable the calcination and sintering processes to be carried out at a shorter time and lower temperature. The x-ray diffraction (XRD) analysis result shows that a single-phase of CaCu(3)Ti(4)O(12) was completely formed by calcination at 750 degrees C for 12 hours. Meanwhile, the grain size of a sample sintered at 1050 degrees C for 24 hours is extremely large, in the range of 20-50 mum obtained from field emission scanning electron microscopy (FESEM) images. The dielectric constant value of 14,635 was obtained at 10 kHz by impedance (LCR) meter in the sintered sample at 1050 degrees C. However, the dielectric constant value of samples sintered at 900 and 950 degrees C is quite low, in the range of 52-119.

Journal of Mechanical Engineering and Sciences, Jun 30, 2014

Lead zirconatetitanate Pb(Zr 0.52 Ti 0.48)O 3 , (PZT) from a mixture of commercial PbO, TiO 2 and... more Lead zirconatetitanate Pb(Zr 0.52 Ti 0.48)O 3 , (PZT) from a mixture of commercial PbO, TiO 2 and ZrO 2 powders was successfully prepared using a planetary ball mill. The microstructure and electrical properties of PZT ceramic were found to be highly sensitive to the sintering condition. The influence of microstructure and electrical properties on the sintering condition of the samples was studied. SEM analysis indicated that a shorter sintering time with higher sintering temperature promotes fine structure and densification. This was proves where the relative density of the sintered PZT ceramics obtained was measured to be approximately 99% of the theoretical density. The electrical properties of the ceramic sintered at a higher temperature with a different sintering time were measured at high frequencies. The result revealed that different sintering conditions have a big impact on electrical behavior in a broad frequency region.

Advanced Materials Research, Dec 1, 2010

Page 1. Crystallite Size of Chitosan Capped Zinc Sulfide Nanoparticles Synthesized via Wet Chemic... more Page 1. Crystallite Size of Chitosan Capped Zinc Sulfide Nanoparticles Synthesized via Wet Chemical Route EVON Y. LIN FOO and SABAR D. HUTAGALUNG* ... [9] AP Alivisatos: Nature, Vol. 382 (1996), p. 609. [10] X. Gao, WC Chan, S. Nie: Science, Vol. 281 (1998), p. 2016. ...

Advanced Materials Research, Oct 1, 2011

CaCu3Ti4O12 (CCTO) is a promising material for microelectronic and microwave device applications ... more CaCu3Ti4O12 (CCTO) is a promising material for microelectronic and microwave device applications due to its unique properties that posses high dielectric constant in the wide temperature range. In this work, atomic force microscopy (AFM) and scanning electron microscopy (SEM) analyses were applied for nanoscale imaging of Nb-doped CCTO grains. The Nb-doped CCTO pellets (CaCu3Ti4-xNbxO12+x/2; x = 0, 0.01, 0.03, 0.05, 0.1) were prepared via solid state reaction method and thermally etched at 940°C for an hour. From AFM and SEM images found that tiny bumped as well as terrace type domains are distributed within a grain. The domain size is ranging from 20 to 180 nm measured by AFM. The existence of domains on grain will produce grain boundary and domain boundary resistance inside CCTO. Both domain and grain resistance are believed to strongly influence the electrical properties of CCTO.

Lecture Notes in Mechanical Engineering, 2019

Silicon nanowires (SiNWs) have been a great candidate to be used in development of electronic dev... more Silicon nanowires (SiNWs) have been a great candidate to be used in development of electronic devices because it is easy to prepare in small dimension with high surface to volume ratio and its sensitivity of the carrier mobility to the variation in the electric field at their surface. Silicon nanowires (SiNWs) can be prepared using both “bottom-up” and “top-down” approached. AFM lithography is one of top-down approach used to fabricate the silicon nanowires by using the local anodic oxidation (LAO) process. The local anodic oxidation process involves the application of a positive voltage between the AFM tip and the surface of the silicon-on-insulator (SOI) wafer in the atmosphere with high relative humidity. The humidity in the ambient will generates a meniscus of water between the AFM tips and SOI wafer. The applied voltage on the tips will ionizes the water molecules and producing OH- ions, which will react with silicon on SOI wafer and form silicon oxide patterned on SOI wafer. Several AFM lithography important parameters in the patterning of the oxide mask, such as substrate surface roughness, applied voltage, writing speed and relative humidity were discussed. After the oxide pattern growth, the SOI wafers were undergo for chemical etching to remove silicon and SiNWs were formed.

2010 International Conference on Computer Applications and Industrial Electronics, 2010

This paper presents a new approach of designing a bandpass filter by applying a combination of mi... more This paper presents a new approach of designing a bandpass filter by applying a combination of microstrip and cylindrical shape of dielectric resonators for X-Band application. Three dielectric resonators with a same permittivity and diameter of 60 and 5 mm respectively are applied in the circuit in order to obtain a wideband of more than 1.0 GHz. The interaction between the microstrip transmission line and dielectric resonators increases the coupling effect as well as minimizing the insertion loss in the filter passband. An analysis on the effect of the height of the dielectric resonators has been investigated in order to prove that the new approach contributes more advantages and viable at the desired application band.

TENCON 2010 - 2010 IEEE Region 10 Conference, 2010

This paper presents a new approach of designing a bandpass filter by applying a combination of mi... more This paper presents a new approach of designing a bandpass filter by applying a combination of microstrip and cylindrical dielectric resonators for X-Band application. Three dielectric resonators with a same permittivity and diameter of 60 and 5 mm respectively are applied in the circuit in order to obtain a wideband of more than 1.0 GHz. The combinations able to increase

2010 IEEE Asia-Pacific Conference on Applied Electromagnetics (APACE), 2010

This paper focuses on the analysis to find suitable locations to place dielectric resonators on m... more This paper focuses on the analysis to find suitable locations to place dielectric resonators on microstrip transmission line in order to obtain a high coupling effect. A novel design of an X-Band bandpass filter from a combination of a simple transmission line and three cylindrical dielectric resonators are used in this analysis. The three dielectric resonators are same in permittivity and radius of 60 and 2.55 mm, respectively. This analysis found that the coupling effect can be maximized by placing dielectric resonators a distance of quarter or half wavelength from each other.

Thin Solid Films, 2009

The physical and electronic properties of 100-120-nm thick anodic silicon dioxide film grown on p... more The physical and electronic properties of 100-120-nm thick anodic silicon dioxide film grown on p-type 4H-SiC wafer and annealed at different temperatures (500, 600, 700, and 800°C) have been investigated and reported. Chemical bonding of the films has been analyzed by Fourier transform infra red spectroscopy. Smooth and defect-free film surface has been revealed under field emission scanning electron microscope. Atomic force microscope has been used to study topography and surface roughness of the films. Electronic properties of the film have been investigated by high frequency capacitance-voltage and current-voltage measurements. As the annealing temperature increased, refractive index, dielectric constant, film density, SiC surface roughness, effective oxide charge, and leakage current density have been reduced until 700°C. An increment of these parameters has been observed after this temperature. However, a reversed trend has been demonstrated in porosity of the film and barrier height between conduction band edge of SiO 2 and SiC.

ABSTRACT P-type transparent conductive oxide of copper aluminum oxide (CuAlO 2) thin films were p... more ABSTRACT P-type transparent conductive oxide of copper aluminum oxide (CuAlO 2) thin films were prepared by using sol-gel method with nitrate solutions as starting precursor. Copper nitrate and aluminum nitrate were selected as raw materials that provide the copper and aluminum source. The CuAlO 2 thin films were deposited on pre-cleaned silicon substrate by spin-coating technique. To study of phase formation of CuAlO 2 , as prepared sample was dried and subjected to heat treatment at various temperatures. The heat-treated samples were characterized by x-ray diffraction (XRD) and energy dispersive x-ray (EDX). From XRD analysis result found that CuAlO 2 phase was formed after annealing at 1100 o C for 4 hrs. EDX result of annealed sample at 1100 o C shows composition of Cu and Al that indicate the possibility of forming CuAlO 2 .

AEU - International Journal of Electronics and Communications, 2013

In this paper, a novel quasi-lumped element resonator antenna is presented. The proposed antenna ... more In this paper, a novel quasi-lumped element resonator antenna is presented. The proposed antenna consists of the interdigital capacitor in parallel with a straight line inductor and is fabricated on Duroid RC4003C circuit board. The entire arrangement was fed by a coaxial feed at a frequency of 5.8 GHz. The size, bandwidth and radiation patterns were studied. The proposed antenna exhibits better impedance bandwidth and significant size reduction in comparison with similar results obtained from the conventional microstrip patch antenna with similar feeding technique and resonant frequency. The size of the proposed antenna structure is 5.8 × 5.6 mm 2 and experimental results are shown to be in good agreement with the design simulation.

Journal of Physics: Conference Series, 2013

This article presents on a simple sub-micron wire fabrication by means of local anodic oxidation ... more This article presents on a simple sub-micron wire fabrication by means of local anodic oxidation atomic force microscopy technique. The silicon-based structure consists of two adjacent terminals serve as probing pads and connected with a wire width less than 200 nm. The pad dimension and wire length are 49 μm2 and 11 μm each, respectively. The fabrication process is conducted at room temperature 24–27 °C with 50–60% relative humidity and operated by commercial atomic force microscopy without any modification done. Furthermore, the local oxidation is performed using gold coated AFM probe tip and assisted by the used of special language supported by the equipment software. In addition, 9.0 V applied voltage with 2 μm / sec writing speed is used to realize the oxidation process. I-V characteristic of bare device shows there is a current flow through the device when a range of voltage is applied. By using this local anodic oxidation technique, the silicon wire-based structure is fabricated and used as gas sensor sensing part. The silicon device demonstrates an increase in resistance as introduced to gas environment. The silicon wire device shows relative sensitivity of 35% to the oxygen gas.

A study on the effect of the modify values of x in CaCu3-xMn4+xO12 system has been carried out wi... more A study on the effect of the modify values of x in CaCu3-xMn4+xO12 system has been carried out with x = 0.1, 0.3, 0.5, 0.7 and 0.9. The materials were prepared via solid-state reaction. The preparation conditions have been optimized using thermogravimetry analysis (TGA) technique. Material formations under the reported conditions have been confirmed by X-ray diffraction (XRD) studies. The results show that the formation of CaCu3Mn4O12 started at calcinations temperature of 600 0 C with the presence of raw material and was formed completely at 850 0 C. Field emission scanning electron microscopy (FESEM) analysis indicated that the increase of x value in the composition had changed the microstructures to be more faceted. The impedance spectrum is characterized by the appearance of two semicircle arcs whose pattern of evolution changes with rise of values x in the CaCu3-xMn4+xMn4O12 system. Bulk resistance (Rb) and grain boundary resistance (Rgb) of CaCu3xMn4+xO12 decreases form 824.24...

Lecture Notes in Electrical Engineering, 2014

ABSTRACT Feed coupling comparative assessment of some selected patch antennas is presented. Diffe... more ABSTRACT Feed coupling comparative assessment of some selected patch antennas is presented. Different available feed configurations were implemented ranging from the conventional microstrip feed line to coaxial feed probe, quarter wavelength feed, inset coupled, and a few available capacitively loaded coupled feed which are also optimized for maximal excitation, and hence, efficiency. Experimental results were understudy and a thorough comparative assessment summary table is presented. It was noted that the inset feed looks more promising.

CaCu3Ti4O12 was synthesized starting from a solution of TiO2 to which Ca and Cu nitrates were add... more CaCu3Ti4O12 was synthesized starting from a solution of TiO2 to which Ca and Cu nitrates were added. Due to the differences in the solubilities of the Ca, Cu and Ti, initial variations from ideal stoichiometry and a high solution pH was necessary to obtain stoichiometric CaCu3Ti4O12 precipitates. As precipitated samples were amorphous with CuO phases observed after drying of the precipitates at 300 o C. CaCu3Ti4O12 phases were observed after heat treatment at 1000 o C. XRD studies show the presence of CuO and TiO2 in addition to the CaCu3Ti4O12 for non-stoichiometric samples. Observations under the SEM show the presence of Cu rich and Ti rich phases in addition to the CaCu3Ti4O12.

Proceedings of SPIE, Feb 20, 1998

ABSTRACT Tin selenide (SnSe) thin films have been prepared by encapsulated selenization technique... more ABSTRACT Tin selenide (SnSe) thin films have been prepared by encapsulated selenization technique. The Sn/Se stacked films were deposited by vacuum evaporation and annealed at 200 degrees Celsius for 3 hours to form a stoichiometric SnSe compound. Optical absorption measurements were made on the as- prepared sample using spectrophotometer in the range from UV to visible region (200 - 900 nm). The absorption coefficient, (alpha) was found to be greater than 105 cm-1 that suggested the occurrence of either indirect allowed or direct forbidden optical transition. A further investigations on the (ahv)1/2 and (ahv)2/3 plots against photon energy have been carried out and the resulting optical bandgap obtained from indirect allowed transitions were 0.95 eV for 40.5 nm sample and reduced to 0.79 eV for 125 nm sample thickness. In the case of direct forbidden transition, the energy gaps were between 1.20 - 1.08 nm. The results also showed that the band gap decreased with increasing sample thickness.

Silicon nanowires were synthesized on Si substrates (111) via thermal evaporation using AuPd thin... more Silicon nanowires were synthesized on Si substrates (111) via thermal evaporation using AuPd thin layer catalyst. Pre cleaned of Si wafer was used as a substrate to assemble the nanostructure products. In this work, the effect of growth temperature that ranging from 800 to 1000 o C on the formation of silicon nanowires studied extensively. X-ray diffraction and field emission scanning electron microscope were employed to characterize the structures and morphology of nanowires. Vertical aligned silicon nanowires have been successfully grown on Si substrates at 900 and 1000 o C. At 1100 o C, the high aspect ratio of silicon nanowires can be produced but the formation density is low. The presence of AuPd catalyst on the tip of nanowires, it is expected that VLS is the most suitable to explain the growth mechanism of obtained SiNWs. The crystalline structure of SiNWs was proved by XRD data. ABSTRAK Silikon nanowires disintesiskan pada substrat Si (111) melalui penyejatan terma menggunakan lapisan nipis AuPd pemangkin. Sebelum dibersihkan Si wafer telah digunakan seperti satu substrat bagi memasang nanostructure produk. Dalam kerja ini, kesan pertumbuhan itu suhu yang meletakkan dari 800 hingga 1000 o C pada pembentukan silikon itu nanowires belajar dengan meluas. Belauan sinar-X dan mikroskop elektron penskanan pancaran medan diambil bekerja untuk mencirikan struktur-struktur itu dan morfologi nanowires. Silikon jajar tegak nanowires telah dengan jayanya ditanam atas substrat Si pada 900 dan 1000 o C. Pada 1100 o C, nisbah aspek atasan silikon nanowires akan dapat dikeluarkan tetapi ketumpatan pembentukan adalah rendah. Kehadiran bagi AuPd pemangkin pada hujung nanowires, ia dijangka yang VLS adalah paling sesuai untuk menjelaskan pertumbuhan mekanisme memperolehi SiNWs. Struktur habluran bagi SiNWs adalah terbukti oleh data XRD.

Journal of physics, Apr 15, 2013

This article presents on a simple sub-micron wire fabrication by means of local anodic oxidation ... more This article presents on a simple sub-micron wire fabrication by means of local anodic oxidation atomic force microscopy technique. The silicon-based structure consists of two adjacent terminals serve as probing pads and connected with a wire width less than 200 nm. The pad dimension and wire length are 49 μm2 and 11 μm each, respectively. The fabrication process is conducted at room temperature 24–27 °C with 50–60% relative humidity and operated by commercial atomic force microscopy without any modification done. Furthermore, the local oxidation is performed using gold coated AFM probe tip and assisted by the used of special language supported by the equipment software. In addition, 9.0 V applied voltage with 2 μm / sec writing speed is used to realize the oxidation process. I-V characteristic of bare device shows there is a current flow through the device when a range of voltage is applied. By using this local anodic oxidation technique, the silicon wire-based structure is fabricated and used as gas sensor sensing part. The silicon device demonstrates an increase in resistance as introduced to gas environment. The silicon wire device shows relative sensitivity of 35% to the oxygen gas.

Procedia Manufacturing, 2015

This article presents a fabrication of junctionless sub-micron silicon wire based device by means... more This article presents a fabrication of junctionless sub-micron silicon wire based device by means of atomic force microscope nanolithography for carbon dioxide and nitrous oxide gas detection. The final product was obtained after a sequence step of silicon and silicon dioxide etching process. The device consisted of three parallel sub-micron silicon wires which connected to two adjacent contact pads. The obtained silicon wires width ranging between 233 nm to 340 nm which fabricated under a controlled environment. This experiment utilized the use of silicon-oninsulator wafer as a raw material and atomic force microscope nanolithography as a method to fabricate the device structure. The bare device was electrically characterized using semiconductor parameter analyzer and behaved as a resistor where there was a current flow from one contact point to another contact point. The functionality of the fabricated junctionless device was prolonged by tested the device under gaseous environment at room temperature. The device resistivity was increased upon exposure to both target gases compared with before gas exposure. The response time and recovery time of the device was observed to be less than 1 minute for both target gases. The fabricated junctionless sub-micron silicon device showed higher sensitivity to carbon dioxide gas which calculated to be 138 %.

IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, Dec 1, 2007

This paper presents the effects of calcination time and sintering temperature on the properties o... more This paper presents the effects of calcination time and sintering temperature on the properties of CaCu(3)Ti(4)O(12). Electroceramic material of CaCu(3)Ti(4)O(12) was prepared using a modified mechanical alloying technique that covers several processes, which are preparation of raw material, mixing and ball milling for 5 hours, calcination, pellet forming and, sintering. The objective of this modified technique is to enable the calcination and sintering processes to be carried out at a shorter time and lower temperature. The x-ray diffraction (XRD) analysis result shows that a single-phase of CaCu(3)Ti(4)O(12) was completely formed by calcination at 750 degrees C for 12 hours. Meanwhile, the grain size of a sample sintered at 1050 degrees C for 24 hours is extremely large, in the range of 20-50 mum obtained from field emission scanning electron microscopy (FESEM) images. The dielectric constant value of 14,635 was obtained at 10 kHz by impedance (LCR) meter in the sintered sample at 1050 degrees C. However, the dielectric constant value of samples sintered at 900 and 950 degrees C is quite low, in the range of 52-119.

Journal of Mechanical Engineering and Sciences, Jun 30, 2014

Lead zirconatetitanate Pb(Zr 0.52 Ti 0.48)O 3 , (PZT) from a mixture of commercial PbO, TiO 2 and... more Lead zirconatetitanate Pb(Zr 0.52 Ti 0.48)O 3 , (PZT) from a mixture of commercial PbO, TiO 2 and ZrO 2 powders was successfully prepared using a planetary ball mill. The microstructure and electrical properties of PZT ceramic were found to be highly sensitive to the sintering condition. The influence of microstructure and electrical properties on the sintering condition of the samples was studied. SEM analysis indicated that a shorter sintering time with higher sintering temperature promotes fine structure and densification. This was proves where the relative density of the sintered PZT ceramics obtained was measured to be approximately 99% of the theoretical density. The electrical properties of the ceramic sintered at a higher temperature with a different sintering time were measured at high frequencies. The result revealed that different sintering conditions have a big impact on electrical behavior in a broad frequency region.

Advanced Materials Research, Dec 1, 2010

Page 1. Crystallite Size of Chitosan Capped Zinc Sulfide Nanoparticles Synthesized via Wet Chemic... more Page 1. Crystallite Size of Chitosan Capped Zinc Sulfide Nanoparticles Synthesized via Wet Chemical Route EVON Y. LIN FOO and SABAR D. HUTAGALUNG* ... [9] AP Alivisatos: Nature, Vol. 382 (1996), p. 609. [10] X. Gao, WC Chan, S. Nie: Science, Vol. 281 (1998), p. 2016. ...

Advanced Materials Research, Oct 1, 2011

CaCu3Ti4O12 (CCTO) is a promising material for microelectronic and microwave device applications ... more CaCu3Ti4O12 (CCTO) is a promising material for microelectronic and microwave device applications due to its unique properties that posses high dielectric constant in the wide temperature range. In this work, atomic force microscopy (AFM) and scanning electron microscopy (SEM) analyses were applied for nanoscale imaging of Nb-doped CCTO grains. The Nb-doped CCTO pellets (CaCu3Ti4-xNbxO12+x/2; x = 0, 0.01, 0.03, 0.05, 0.1) were prepared via solid state reaction method and thermally etched at 940°C for an hour. From AFM and SEM images found that tiny bumped as well as terrace type domains are distributed within a grain. The domain size is ranging from 20 to 180 nm measured by AFM. The existence of domains on grain will produce grain boundary and domain boundary resistance inside CCTO. Both domain and grain resistance are believed to strongly influence the electrical properties of CCTO.

Lecture Notes in Mechanical Engineering, 2019

Silicon nanowires (SiNWs) have been a great candidate to be used in development of electronic dev... more Silicon nanowires (SiNWs) have been a great candidate to be used in development of electronic devices because it is easy to prepare in small dimension with high surface to volume ratio and its sensitivity of the carrier mobility to the variation in the electric field at their surface. Silicon nanowires (SiNWs) can be prepared using both “bottom-up” and “top-down” approached. AFM lithography is one of top-down approach used to fabricate the silicon nanowires by using the local anodic oxidation (LAO) process. The local anodic oxidation process involves the application of a positive voltage between the AFM tip and the surface of the silicon-on-insulator (SOI) wafer in the atmosphere with high relative humidity. The humidity in the ambient will generates a meniscus of water between the AFM tips and SOI wafer. The applied voltage on the tips will ionizes the water molecules and producing OH- ions, which will react with silicon on SOI wafer and form silicon oxide patterned on SOI wafer. Several AFM lithography important parameters in the patterning of the oxide mask, such as substrate surface roughness, applied voltage, writing speed and relative humidity were discussed. After the oxide pattern growth, the SOI wafers were undergo for chemical etching to remove silicon and SiNWs were formed.

2010 International Conference on Computer Applications and Industrial Electronics, 2010

This paper presents a new approach of designing a bandpass filter by applying a combination of mi... more This paper presents a new approach of designing a bandpass filter by applying a combination of microstrip and cylindrical shape of dielectric resonators for X-Band application. Three dielectric resonators with a same permittivity and diameter of 60 and 5 mm respectively are applied in the circuit in order to obtain a wideband of more than 1.0 GHz. The interaction between the microstrip transmission line and dielectric resonators increases the coupling effect as well as minimizing the insertion loss in the filter passband. An analysis on the effect of the height of the dielectric resonators has been investigated in order to prove that the new approach contributes more advantages and viable at the desired application band.

TENCON 2010 - 2010 IEEE Region 10 Conference, 2010

This paper presents a new approach of designing a bandpass filter by applying a combination of mi... more This paper presents a new approach of designing a bandpass filter by applying a combination of microstrip and cylindrical dielectric resonators for X-Band application. Three dielectric resonators with a same permittivity and diameter of 60 and 5 mm respectively are applied in the circuit in order to obtain a wideband of more than 1.0 GHz. The combinations able to increase

2010 IEEE Asia-Pacific Conference on Applied Electromagnetics (APACE), 2010

This paper focuses on the analysis to find suitable locations to place dielectric resonators on m... more This paper focuses on the analysis to find suitable locations to place dielectric resonators on microstrip transmission line in order to obtain a high coupling effect. A novel design of an X-Band bandpass filter from a combination of a simple transmission line and three cylindrical dielectric resonators are used in this analysis. The three dielectric resonators are same in permittivity and radius of 60 and 2.55 mm, respectively. This analysis found that the coupling effect can be maximized by placing dielectric resonators a distance of quarter or half wavelength from each other.

Thin Solid Films, 2009

The physical and electronic properties of 100-120-nm thick anodic silicon dioxide film grown on p... more The physical and electronic properties of 100-120-nm thick anodic silicon dioxide film grown on p-type 4H-SiC wafer and annealed at different temperatures (500, 600, 700, and 800°C) have been investigated and reported. Chemical bonding of the films has been analyzed by Fourier transform infra red spectroscopy. Smooth and defect-free film surface has been revealed under field emission scanning electron microscope. Atomic force microscope has been used to study topography and surface roughness of the films. Electronic properties of the film have been investigated by high frequency capacitance-voltage and current-voltage measurements. As the annealing temperature increased, refractive index, dielectric constant, film density, SiC surface roughness, effective oxide charge, and leakage current density have been reduced until 700°C. An increment of these parameters has been observed after this temperature. However, a reversed trend has been demonstrated in porosity of the film and barrier height between conduction band edge of SiO 2 and SiC.

ABSTRACT P-type transparent conductive oxide of copper aluminum oxide (CuAlO 2) thin films were p... more ABSTRACT P-type transparent conductive oxide of copper aluminum oxide (CuAlO 2) thin films were prepared by using sol-gel method with nitrate solutions as starting precursor. Copper nitrate and aluminum nitrate were selected as raw materials that provide the copper and aluminum source. The CuAlO 2 thin films were deposited on pre-cleaned silicon substrate by spin-coating technique. To study of phase formation of CuAlO 2 , as prepared sample was dried and subjected to heat treatment at various temperatures. The heat-treated samples were characterized by x-ray diffraction (XRD) and energy dispersive x-ray (EDX). From XRD analysis result found that CuAlO 2 phase was formed after annealing at 1100 o C for 4 hrs. EDX result of annealed sample at 1100 o C shows composition of Cu and Al that indicate the possibility of forming CuAlO 2 .

AEU - International Journal of Electronics and Communications, 2013

In this paper, a novel quasi-lumped element resonator antenna is presented. The proposed antenna ... more In this paper, a novel quasi-lumped element resonator antenna is presented. The proposed antenna consists of the interdigital capacitor in parallel with a straight line inductor and is fabricated on Duroid RC4003C circuit board. The entire arrangement was fed by a coaxial feed at a frequency of 5.8 GHz. The size, bandwidth and radiation patterns were studied. The proposed antenna exhibits better impedance bandwidth and significant size reduction in comparison with similar results obtained from the conventional microstrip patch antenna with similar feeding technique and resonant frequency. The size of the proposed antenna structure is 5.8 × 5.6 mm 2 and experimental results are shown to be in good agreement with the design simulation.

Journal of Physics: Conference Series, 2013

This article presents on a simple sub-micron wire fabrication by means of local anodic oxidation ... more This article presents on a simple sub-micron wire fabrication by means of local anodic oxidation atomic force microscopy technique. The silicon-based structure consists of two adjacent terminals serve as probing pads and connected with a wire width less than 200 nm. The pad dimension and wire length are 49 μm2 and 11 μm each, respectively. The fabrication process is conducted at room temperature 24–27 °C with 50–60% relative humidity and operated by commercial atomic force microscopy without any modification done. Furthermore, the local oxidation is performed using gold coated AFM probe tip and assisted by the used of special language supported by the equipment software. In addition, 9.0 V applied voltage with 2 μm / sec writing speed is used to realize the oxidation process. I-V characteristic of bare device shows there is a current flow through the device when a range of voltage is applied. By using this local anodic oxidation technique, the silicon wire-based structure is fabricated and used as gas sensor sensing part. The silicon device demonstrates an increase in resistance as introduced to gas environment. The silicon wire device shows relative sensitivity of 35% to the oxygen gas.

A study on the effect of the modify values of x in CaCu3-xMn4+xO12 system has been carried out wi... more A study on the effect of the modify values of x in CaCu3-xMn4+xO12 system has been carried out with x = 0.1, 0.3, 0.5, 0.7 and 0.9. The materials were prepared via solid-state reaction. The preparation conditions have been optimized using thermogravimetry analysis (TGA) technique. Material formations under the reported conditions have been confirmed by X-ray diffraction (XRD) studies. The results show that the formation of CaCu3Mn4O12 started at calcinations temperature of 600 0 C with the presence of raw material and was formed completely at 850 0 C. Field emission scanning electron microscopy (FESEM) analysis indicated that the increase of x value in the composition had changed the microstructures to be more faceted. The impedance spectrum is characterized by the appearance of two semicircle arcs whose pattern of evolution changes with rise of values x in the CaCu3-xMn4+xMn4O12 system. Bulk resistance (Rb) and grain boundary resistance (Rgb) of CaCu3xMn4+xO12 decreases form 824.24...

Lecture Notes in Electrical Engineering, 2014

ABSTRACT Feed coupling comparative assessment of some selected patch antennas is presented. Diffe... more ABSTRACT Feed coupling comparative assessment of some selected patch antennas is presented. Different available feed configurations were implemented ranging from the conventional microstrip feed line to coaxial feed probe, quarter wavelength feed, inset coupled, and a few available capacitively loaded coupled feed which are also optimized for maximal excitation, and hence, efficiency. Experimental results were understudy and a thorough comparative assessment summary table is presented. It was noted that the inset feed looks more promising.

CaCu3Ti4O12 was synthesized starting from a solution of TiO2 to which Ca and Cu nitrates were add... more CaCu3Ti4O12 was synthesized starting from a solution of TiO2 to which Ca and Cu nitrates were added. Due to the differences in the solubilities of the Ca, Cu and Ti, initial variations from ideal stoichiometry and a high solution pH was necessary to obtain stoichiometric CaCu3Ti4O12 precipitates. As precipitated samples were amorphous with CuO phases observed after drying of the precipitates at 300 o C. CaCu3Ti4O12 phases were observed after heat treatment at 1000 o C. XRD studies show the presence of CuO and TiO2 in addition to the CaCu3Ti4O12 for non-stoichiometric samples. Observations under the SEM show the presence of Cu rich and Ti rich phases in addition to the CaCu3Ti4O12.