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Papers by khondoker hossain

Research paper thumbnail of Simulation and Study the Performance of the Absorbing Layer for a Silicon (Si) PIN Solar Cell

Under this project wok, we have studied the performance of absorbing layer on top of a PIN Si th... more Under this project wok, we have studied the performance of absorbing layer on top of a PIN Si thin film solar cell. We have used online simulation tool from nanohub.org to do the desired calculations. The transport layer is composed of PIN Si structure with a total maximumthickness of around 600 nm. The absorption layer is considered to be of GaAs and Ge. The thickness of both of them have been varied from 50 nm to 200 nm. Absorption coefficient, induced current and percentage of convertible power have been calculated. It was found that current gets saturated at a certain absorber thickness which is 100 nm for Ge and 200nm for GaAs. Ge shows a slight higher absorption coefficient than GaAs whereas, percentage of convertible power was higher for GaAs compared to Ge.

Research paper thumbnail of Effects of various filter parameters on the Myocardial Perfusion with Polar plot image

— In Single Photon Emission Computed Tomography (SPECT), Myocardial Perfusion is visualized in Sh... more — In Single Photon Emission Computed Tomography (SPECT), Myocardial Perfusion is visualized in Short Axis (SA), Horizontal Long Axis (HLA), and Vertical Long Axis (VLA) slices of Left Ventricle (LV). Filtered Back Projection (FBP) is used as an image reconstruction algorithm in SPECT study. The choice of appropriate filter is a trade-off between image smoothness and sharpness of reconstructed images. The purpose of this study is to evaluate the effects of several filters including Butterworth, Generalized Hanning, Shepp Logan, Parzen filters with varying filter parameters (cutoff and order). Our finding is that Butterworth filter at cutoff 0.40 Nyquist, Parzen filter at cutoff 0.80 Nyquist, Hanning filter at 0.70 Nyquist and Shepp Logan filter at 0.50 Nyquist produce better image quality. For easier and more objective assessment of Myocardial Perfusion, Polar Plot display is introduced that represents tomographic slices in a single image (2D display) where information contained in the Short Axis slices of the Left Ventricle.

Drafts by khondoker hossain

Research paper thumbnail of Developing and Characterization of Silver Nanoparticles Synthesized by Electroless Metal Deposition

In this work silicon nanowires (SiNWs) are intended to be grown on Si wafer surface following a ... more In this work silicon nanowires (SiNWs) are intended to be grown on Si wafer surface following a bottom-up approach by depositing Ag nanoparticles over P-type Si substrate and then etched. It is a simple electroless metal deposition and wet etching process. Different samples are prepared varying the amount of Ag deposition over the Si substrate surface and changing the parameters of etching. Presence of nanoparticles of Ag are evident from the top view SEM (Scanning electron microscope) images of different samples. Also EDX (Energy-dispersive X-ray spectroscopy) is carried out for the samples and we found the amount of Ag and Si in percentage on different point over the surface of the samples. According to the study of UV (Ultra Violet) spectrophotometer, our synthesized structures show higher absorption than the bulk Si in the wavelength range of 400 nm to 1000 nm. We changed deposition time of Ag, etching time and concentration of HF solution for preparing different samples. We tried to explain the changes in UV absorption data of different samples for varying these parameters. This observation supports that our synthesized structure might be a potential candidate for efficient photovoltaic solar cell and other optoelectronic devices.

Keywords: Silicon Nanowires (SiNWs), Electroless Metal Deposition and Etching (EMDE), Photovoltaic (PV), Optical absorption

Research paper thumbnail of Simulation and Study the Performance of the Absorbing Layer for a Silicon (Si) PIN Solar Cell

Under this project wok, we have studied the performance of absorbing layer on top of a PIN Si th... more Under this project wok, we have studied the performance of absorbing layer on top of a PIN Si thin film solar cell. We have used online simulation tool from nanohub.org to do the desired calculations. The transport layer is composed of PIN Si structure with a total maximumthickness of around 600 nm. The absorption layer is considered to be of GaAs and Ge. The thickness of both of them have been varied from 50 nm to 200 nm. Absorption coefficient, induced current and percentage of convertible power have been calculated. It was found that current gets saturated at a certain absorber thickness which is 100 nm for Ge and 200nm for GaAs. Ge shows a slight higher absorption coefficient than GaAs whereas, percentage of convertible power was higher for GaAs compared to Ge.

Research paper thumbnail of Effects of various filter parameters on the Myocardial Perfusion with Polar plot image

— In Single Photon Emission Computed Tomography (SPECT), Myocardial Perfusion is visualized in Sh... more — In Single Photon Emission Computed Tomography (SPECT), Myocardial Perfusion is visualized in Short Axis (SA), Horizontal Long Axis (HLA), and Vertical Long Axis (VLA) slices of Left Ventricle (LV). Filtered Back Projection (FBP) is used as an image reconstruction algorithm in SPECT study. The choice of appropriate filter is a trade-off between image smoothness and sharpness of reconstructed images. The purpose of this study is to evaluate the effects of several filters including Butterworth, Generalized Hanning, Shepp Logan, Parzen filters with varying filter parameters (cutoff and order). Our finding is that Butterworth filter at cutoff 0.40 Nyquist, Parzen filter at cutoff 0.80 Nyquist, Hanning filter at 0.70 Nyquist and Shepp Logan filter at 0.50 Nyquist produce better image quality. For easier and more objective assessment of Myocardial Perfusion, Polar Plot display is introduced that represents tomographic slices in a single image (2D display) where information contained in the Short Axis slices of the Left Ventricle.

Research paper thumbnail of Developing and Characterization of Silver Nanoparticles Synthesized by Electroless Metal Deposition

In this work silicon nanowires (SiNWs) are intended to be grown on Si wafer surface following a ... more In this work silicon nanowires (SiNWs) are intended to be grown on Si wafer surface following a bottom-up approach by depositing Ag nanoparticles over P-type Si substrate and then etched. It is a simple electroless metal deposition and wet etching process. Different samples are prepared varying the amount of Ag deposition over the Si substrate surface and changing the parameters of etching. Presence of nanoparticles of Ag are evident from the top view SEM (Scanning electron microscope) images of different samples. Also EDX (Energy-dispersive X-ray spectroscopy) is carried out for the samples and we found the amount of Ag and Si in percentage on different point over the surface of the samples. According to the study of UV (Ultra Violet) spectrophotometer, our synthesized structures show higher absorption than the bulk Si in the wavelength range of 400 nm to 1000 nm. We changed deposition time of Ag, etching time and concentration of HF solution for preparing different samples. We tried to explain the changes in UV absorption data of different samples for varying these parameters. This observation supports that our synthesized structure might be a potential candidate for efficient photovoltaic solar cell and other optoelectronic devices.

Keywords: Silicon Nanowires (SiNWs), Electroless Metal Deposition and Etching (EMDE), Photovoltaic (PV), Optical absorption

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