Prabakaran Poopalan | Universiti Malaysia Perlis (UniMAP) (original) (raw)

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Papers by Prabakaran Poopalan

EPJ Web of Conferences, 2017

MATEC Web of Conferences, 2016

2011 IEEE Regional Symposium on Micro and Nano Electronics, 2011

The effect of the film thickness of the ferroelectric barium strontium titanate thin films at the... more The effect of the film thickness of the ferroelectric barium strontium titanate thin films at the memory behavior of ferroelectric-gate field effect transistor (FeFET) has been studied. The films have been fabricated as metal-ferroelectric-insulator-semiconductor (MFIS) configuration using sol-gel technique. In order to investigate the memory window behavior, the C-V measurements have been carried out for the prepared samples at different applied voltage values. The results show that the memory window width increases with the increase of the film thickness, which is attributed to the grain size effect. It is found also that the memory window increases as the applied voltage increases. The leakage current of the films has been presented to study the interface behavior of the gate junction; the result shows that the leakage current increases with increasing the film thickness. Furthermore, it is found that for all the tested samples the leakage current density is of order 10−8 A/cm2. These values of the current density are relatively low, leading to good interfaces situation.

Applied Nanoscience, 2011

Zeitschrift für Naturforschung A, 2011

Sol-gel barium strontium titanate ( Ba0.6Sr0.4TiO3) thin films with different grain sizes have be... more Sol-gel barium strontium titanate ( Ba0.6Sr0.4TiO3) thin films with different grain sizes have been successfully fabricated as metal-insulator-metal (MIM) capacitors. The perovskite structure of the material has been confirmed via X-ray diffraction (XRD). In order to correlate the effect of the grain size to the conduction mechanisms of these films, atomic force microscopy (AFM) results are presented. The grain size shows an important effect on the conduction mechanism for the films. The results show that as the grain size increases, both the impedance and the permittivity of the films decrease, whereas the conductivity shows an inverse variation. The Z* plane for all films shows two regions, corresponding to the bulk mechanism and the distribution of the grain boundaries-electrodes conduction process.M´´ versus frequency plots reveal non-Debye relaxation peaks, which are not able to be observed in the e´´ plots. Alternating current (AC) conductivity versus frequency plots show thre...

Jurnal Teknologi, 2002

Kaedah untuk menghasilkan peranti FBG yang mempunyai peratus pantulan yang tinggi diperkenalkan. ... more Kaedah untuk menghasilkan peranti FBG yang mempunyai peratus pantulan yang tinggi diperkenalkan. Peranti FBG telah dicetak dalam gentian optik khas yang mengandungi germanium dan boron yang tinggi. Kandungan germanium ion di dalam gentian optik teras adalah sebanyak mol 20%. Cara yang digunakan ialah cara percetakan topeng fasa dengan menggunakan cahaya ultra ungu ion yang mempunyai panjang gelombang 244 nm sebagai sumber cahaya. Kami telah berjaya menghasilkan FBG yang mempunyai peratus pantulan setinggi 99.9% dan masa yang diambil untuk cetakan adalah kurang daripada 10 minit. Kata kunci: gentian optik; peranti FBG; laser UV; panjang gelombang Bragg; topeng fasa A technique to fabricate high reflectivity fiber Bragg gratings (FBGs) with minimal optics is presented. The FBG is written in high germania boron co-doped optical fiber using a phase mask with a 244 nm continuous-wave UV light as the printing source. The mol percentage of germania ion in the fiber core is about 20%. We ha...

Optical Communications and Networks, 2002

ABSTRACT

Micro/Nano Materials, Devices, and Systems, 2013

ABSTRACT Surface functionalization studies for re-creating a ‘Lotus Leaf’ effect (superhydrophobi... more ABSTRACT Surface functionalization studies for re-creating a ‘Lotus Leaf’ effect (superhydrophobic) have been carried out for the past decade; looking for the material which can provide high transparency, low energy surface and high surface roughness. Fabrication of polydimethylsiloxane (PDMS) and multiwalled carbon nanotubes (MWCNT) hybrid thin film variations on glass to produce near-superhydrophobic surfaces is presented in this paper. There are three important parameters studied in producing hydrophobic surfaces based on the hybrid thin films; concentration of PDMS, concentration of MWCNT and droplet sizes. The study is carried out by using PDMS of varied cross linker ratio (10:1, 30:1 and 50:1) with MWCNT concentration of 1mg, 10mg and 15mg for 0.5 μl, 2.0 μl, 5.0 μl and 10 μl droplet sizes. The resulting hybrid thin films show that hydrophobicity increased with increasing cross linker ratio and MWCNT percentage in the PDMS solution. A near superhydrophobic surface can be created when using 15 mg of MWCNT with 50:1 cross linker ratio PDMS thin films, measured on 10 μl droplet size. The hybrid thin films produced can be potentially tailored to the application of biosensors, MEMS and even commercial devices.

The eect of incorporating a fiber Bragg grating (FBG) in long wavelength band erbium-doped fiber ... more The eect of incorporating a fiber Bragg grating (FBG) in long wavelength band erbium-doped fiber laser (L-band EDFL) is investigated. The EDFLs with and without the FBG operate at wavelength of 1579.3 and 1591.9 nm, respectively. At low pump power, the system without the FBG shows a lower threshold and a better slope eciency compared to that of the system with the FBG. However, the out- put power is reduced at higher pump power due to the mode competition in the cavity. By incorporating the FBG in the laser cavity, the side mode suppression ratio (SMSR) of the laser is significantly improved and a higher output power can be obtained at high pump power. At pump power of 99 mW, the EDFL with the FBG has output power of 11.9 dBm, a 3 dB bandwidth of 0.06 nm and a SMSR of 59 dB.

Physica B: Condensed Matter, 2011

Microwave and Optical Technology Letters, 2003

Microwave and Optical Technology Letters, 2001

Microsystem Technologies, 2011

Journal of Modern Optics, 2000

Journal of Alloys and Compounds, 2011

Sol–gel barium strontium titanate thin films with different barium-to-strontium (Ba:Sr) values ha... more Sol–gel barium strontium titanate thin films with different barium-to-strontium (Ba:Sr) values have been fabricated as MFM configurations. The Perovskite phase for the films is confirmed via XRD. In order to correlate the effect of the chemical composition of the films with the conduction mechanism, different AC electrical parameters have been addressed. The results show that the impedance and dielectric constant decrease as Ba content in the film increases, whereas the conductivity shows the opposite variation; this is attributed to the grain size and dipole dynamics. Complex impedance (Z*) and electric modulus (M*) planes show three overlapping regions as the response for the bulk, the grain boundaries and the film/electrode interface mechanisms. These mechanisms have been represented by an equivalent circuit. The imaginary component of electric modulus (M″) versus frequency plots, which reveal relaxation peaks that are not observed in the dielectric loss (ɛ″) plots, and it is found that these peaks are of a non-Debye-type. Furthermore, the frequency dependent conductivity plot shows three regions of conduction processes.

Japanese Journal of Applied Physics, 2002