Enhancing Performance of Porous Si-Doped GaN based MSM Photodetector Using AC Technique

In this work, we report the formation of porous Si-doped GaN films under a novel alternating current (sine-wave a.c. (50 Hz)) photo-assisted electrochemical etching (ACPEC) conditions. The formation of porous Si-doped GaN by the novel ACPEC is performed in the same electrolyte concentration (4% KOH) used in common de constant current electrochemical etching process. Ultra-violet (UV) illumination is used to assist in the generation of electron-hole pairs, where etching proceeds through the oxidation and consequently, dissolution of the semiconductor surface. The ac formed porous Si-doped GaN with excellent structural and optical properties. According to the FESEM micrographs, the GaN thin films exhibit a homogeneous nanoporous structures with spatial nano-flakes arrangement. The porous layer exhibited a substantial photoluminescence (PL) intensity enhancement with red-shifted band-edge PL peaks associated with the relaxation of compressive stress. The shift of E2(high) to the lower frequency in Raman spectra of the porous GaN films further confirms such a stress relaxation. Electrical characterizations of the MSM photodiodes were carried out by using current-voltage (1-V) measurements indicated that the devices were highly sensitive to ambient light

Penggunaan Mesin Basuh dan Dobi untuk Penyucian Pakaian Bernajis: Analisis Menurut Perspektif Fiqh dan Sains

Pada masa kini, timbul keraguan sesetengah pihak terhadap keupayaan mesin basuh dan mesin dobi menghilangkan najis kerana penggunaan mesin-mesin tersebut tidak pernah dibincangkan oleh fuqaha silam. Justeru itu, kajian ini bertujuan untuk mengenalpasti kenyahwujudan kesan najis selepas dibasuh berpandukan metod basuhan mengikut mazhab Syafie. Sebanyak tiga sampel najis iaitu darah, air kencing dan najis bayi telah digunakan pada pakaian. Pengujian semua sampel telah menggunakan dua kaedah iaitu ujian saringan Kestle-Meyer Test (KM-Test) dan Analisis Profil DNA Forensik di makmal forensik Jabatan Kimia Malaysia Negeri Pulau Pinang. Melalui keputusan ujian KM-Test ke atas sampel yang mengandungi darah telah menunjukkan keputusan negatif. Manakala sampel air kencing dan najis bayi tidak dapat dikesan langsung. Di samping itu, hasil analisis profil DNA turut menunjukkan keputusan serupa iaitu sebelum dibasuh, kehadiran najis pada sampel kawalan darah dikesan hanya pada 44.80 ng/µl (sampel A) dan 65. 00 ng/µl (sampel B) dan selepas dibasuh, kesan yang tinggal pada sampel A dan B basuhan dobi hanya 1.78 ng/µl dan 3.28 ng/µl Manakala pada basuhan mesin basuh, hanya terdapat 3.28 ng/µl pada sampel A dan 1.11 ng/µl pada sampel B. Seterusnya kajian ini merumuskan bahawa basuhan mesin basuh dan dobi berjaya menghilangkan kesan najis dari pakaian. Nowadays, some people have a doubts about the ability of washing machine and laundry machine to remove impurities (najis) because the use of these machines has never been discussed by fuqaha in the past. Therefore, this study aimed to identify the existence of impurities after washing according to the method of purification of Syafie's Mazhab. Three samples of blood, urine and baby stool were used on the clothes. All samples were tested using two methods - the Kestle-Meyer Test (KM-Test) and Forensic DNA Profile Analysis at the Penang State Department of Chemistry Forensic Lab. The results of the KM-Test test on blood samples have shown negative results. While urine samples and baby stools cannot be detected directly. In addition, the DNA profile analysis also showed similar results that before washing, the presence of najis in blood control samples was detected only at 44.80 ng / μl (sample A) and 65. 00 ng / μl (sample B) and after washing, the effect on samples A and B in the laundry wash were only 1.78 ng / μl and 3.28 ng / μl. While in the washing machine, there were only 3.28 ng / μl in sample A and 1.11 ng / μl in sample B. Furthermore, this study concluded that washing machine and laundry machine successfully removes the impurities from clothing.Nowadays, some people have a doubts about the ability of washing machine and laundry machine to remove impurities (najis) because the use of these machines has never been discussed by fuqaha in the past. Therefore, this study aimed to identify the existence of impurities after washing according to the method of purification of Syafie's Mazhab. Three samples of blood, urine and baby stool were used on the clothes. All samples were tested using two methods - the Kestle-Meyer Test (KM-Test) and Forensic DNA Profile Analysis at the Penang State Department of Chemistry Forensic Lab. The results of the KM-Test test on blood samples have shown negative results. While urine samples and baby stools cannot be detected directly. In addition, the DNA profile analysis also showed similar results that before washing, the presence of najis in blood control samples was detected only at 44.80 ng / μl (sample A) and 65. 00 ng / μl (sample B) and after washing, the effect on samples A and B in the laundry wash were only 1.78 ng / μl and 3.28 ng / μl. While in the washing machine, there were only 3.28 ng / µl in sample A and 1.11 ng / µl in sample B. Furthermore, this study concluded that washing machine and laundry machine successfully removes the impurities from clothing

Enhancing Performance Of Porous Si-Doped GaN Based Msm Photodetector Using 50 Hz Acpec

In this work, we report the formation of porous Si-doped GaN films under a novel alternating current (sine-wave a.c. (50 Hz)) photo-assisted electrochemical etching (ACPEC) conditions. The formation of porous Si-doped GaN by the novel ACPEC is performed in the same electrolyte concentration (4% KOH) used in common dc constant current electrochemical etching process. Ultra-violet (UV) illumination is used to assist in the generation of electron-hole pairs, where etching proceeds through the oxidation and consequently, dissolution of the semiconductor surface. The ac formed porous Si-doped GaN with excellent structural and optical properties. According to the FESEM micrographs, the GaN thin films exhibit a homogeneous nanoporous structures with spatial nano-flakes arrangement. The porous layer exhibited a substantial photoluminescence (PL) intensity enhancement with red-shifted band-edge PL peaks associated with the relaxation of compressive stress. The shift of E2(high) to the lower frequency in Raman spectra of the porous GaN films further confirms such a stress relaxation. Electrical characterizations of the MSM photodiodes were carried out by using current-voltage (I-V) measurements indicated that the devices were highly sensitive to ambient light

Study of low dimensional SiGe island on Si for potential visible Metal-Semiconductor-Metal photodetector

In this paper, an investigation of design and simulation of silicon germanium (SiGe) islands on silicon (Si) was presented for potential visible metal semiconductor metal (MSM) photodetector. The characterization of the performances in term of the structural, optical and electrical properties of the structures was analyzed from the simulation results. The project involves simulation using SILVACO Technology Computer Aided Design (TCAD) tools. The different structures of the silicon germanium (SiGe) island on silicon substrate were created, which were large SiGe, small SiGe, combination SiGe and bulk Ge. All the structures were tested for potential Metal Semiconductor Metal (MSM) photodetector. The extracted data such as current versus voltage characteristic, current gain and spectral response were obtained using ATLAS SILVACO tools. The performance of SiGe island structures and bulk Ge on Si substrate as (MSM) photodetector was evaluated by photo and dark current-voltage (I-V) characteristics. It was found that SiGe islands exhibited higher energy band gap compared to bulk Ge. The SiGe islands current-voltage characteristics showed improved current gain compared to bulk Ge. Specifically the enhancement of the islands gain was contributed by the enhanced photo currents and lower dark currents. The spectral responses of the SiGe islands showed peak response at 590 nm (yellow) which is at the visible wavelength. This shows the feasibility of the SiGe islands to be utilized for visible photodetections

Study of low dimensional SiGe island on Si for potential visible Metal-Semiconductor-Metal photodetector

In this paper, an investigation of design and simulation of silicon germanium (SiGe) islands on silicon (Si) was presented for potential visible metal semiconductor metal (MSM) photodetector. The characterization of the performances in term of the structural, optical and electrical properties of the structures was analyzed from the simulation results. The project involves simulation using SILVACO Technology Computer Aided Design (TCAD) tools. The different structures of the silicon germanium (SiGe) island on silicon substrate were created, which were large SiGe, small SiGe, combination SiGe and bulk Ge. All the structures were tested for potential Metal Semiconductor Metal (MSM) photodetector. The extracted data such as current versus voltage characteristic, current gain and spectral response were obtained using ATLAS SILVACO tools. The performance of SiGe island structures and bulk Ge on Si substrate as (MSM) photodetector was evaluated by photo and dark current-voltage (I-V) characteristics. It was found that SiGe islands exhibited higher energy band gap compared to bulk Ge. The SiGe islands current-voltage characteristics showed improved current gain compared to bulk Ge. Specifically the enhancement of the islands gain was contributed by the enhanced photo currents and lower dark currents. The spectral responses of the SiGe islands showed peak response at 590 nm (yellow) which is at the visible wavelength. This shows the feasibility of the SiGe islands to be utilized for visible photodetections

High Sensitivity of Porous Si-Doped GaN MSM Photodetector using Thermally Untreated Platinum Contact

this work. we report the formation of porous Si-doped GaN films under a novel alternating current (sine-wave a.c. (50 Hz)) photo-assisted electrochemical (ACPEC) etching conditions. The ACPEC formed porous GaN with excellent structural and surface morphology. Field emission scanning electron microscope (FESEM), atomic force microscopy (AFM), photoluminescence (PL), Raman spectra and high resolution X-ray diffraction (HR-XRD) phi-scan and rocking curves measurements evidenced important features of the pore morphology, nanostructures and optical properties. According to the FESEM micrographs, the GaN thin films exhibit a homogeneous nanoporous structures with spatial nano-flakes arrangement. The AFM measurements revealed an increase in the surface roughness induced by porosification. The porous layer exhibited a substantial PL intensity enhancement with red-shifted band-edge PL peaks associated with the relaxation of compressive stress. The shift of E2(high) to the lower frequency in Raman spectra of the porous GaN films further confirms such a stress relaxation. X-ray diffraction phi-scan showed that porous GaN sample maintained the epitaxial features. Thermally untreated platinum (Pt) finger contact was deposited on the porous GaN to form MSM photodetector. The current-voltage (I-V) measurements indicated that the devices were highly sensitive to ambient light. The photocurrent rise and decay times were investigated under 365 nm chopped light and at bias voltages of 1, 3 and 5 V