Pub Date : 2014-10-13DOI: 10.1109/SMELEC.2014.6920786
M. Fathil, M. K. Md Arshad, U. Hashim, A. R. Ruslinda, R. Ayub, A. H. Azman, M. Nurfaiz, M. Z. Kamarudin, M. Aminuddin, A. Munir
This paper deals with minority carrier lifetime and carrier concentration of Cu(In, Ga)Se2 (CIGS)-based thin film solar cells with a ZnS(n)/CIGS(p) heterojunction structure. The structure is simulated in commercial numerical simulation and the impact of minority carrier lifetime in the CIGS absorber layer on the open circuit voltage, short circuit current density, fill factor and efficiency of the CIGS solar cell are investigated. The increase of minority carrier lifetime has also increased the CIGS solar cell performance. Similar effects are also observed at different carrier concentrations of CIGS layer. All these simulated results give a helpful indication for a practical fabrication process.
{"title":"The impact of minority carrier lifetime and carrier concentration on the efficiency of CIGS solar cell","authors":"M. Fathil, M. K. Md Arshad, U. Hashim, A. R. Ruslinda, R. Ayub, A. H. Azman, M. Nurfaiz, M. Z. Kamarudin, M. Aminuddin, A. Munir","doi":"10.1109/SMELEC.2014.6920786","DOIUrl":"https://doi.org/10.1109/SMELEC.2014.6920786","url":null,"abstract":"This paper deals with minority carrier lifetime and carrier concentration of Cu(In, Ga)Se2 (CIGS)-based thin film solar cells with a ZnS(n)/CIGS(p) heterojunction structure. The structure is simulated in commercial numerical simulation and the impact of minority carrier lifetime in the CIGS absorber layer on the open circuit voltage, short circuit current density, fill factor and efficiency of the CIGS solar cell are investigated. The increase of minority carrier lifetime has also increased the CIGS solar cell performance. Similar effects are also observed at different carrier concentrations of CIGS layer. All these simulated results give a helpful indication for a practical fabrication process.","PeriodicalId":268203,"journal":{"name":"2014 IEEE International Conference on Semiconductor Electronics (ICSE2014)","volume":"77 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128283552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-13DOI: 10.1109/SMELEC.2014.6920842
Muhammad Zulkhairi Roslan, D. Berhanuddin, M. A. Mohamed, M. F. Mohd Razip Wee, F. Larki, B. Majlis
Damage profiling of implanted ions in semiconductor's layer is crucial in order to accurately estimate the ion distribution and concentration in the target substrates. It also gives the predicted number of vacancies and interstitials after the collision events. This is particularly important prior to the ion implantation so as to reduce the defect formation and damage to the target's lattice which subsequently degrade the performance of the device. In this paper, we studied the optimized energy and range of ions implanted silicon in In0.53Ga0.47As film by utilizing the Stopping Range of Ions in Matter (SRIM) simulation. The effects of implantation energy in different thickness are also discussed based on creation of phonons, vacancies and ionization.
{"title":"Structural damage of Si-implanted in the In0.53Ga0.47As thin film","authors":"Muhammad Zulkhairi Roslan, D. Berhanuddin, M. A. Mohamed, M. F. Mohd Razip Wee, F. Larki, B. Majlis","doi":"10.1109/SMELEC.2014.6920842","DOIUrl":"https://doi.org/10.1109/SMELEC.2014.6920842","url":null,"abstract":"Damage profiling of implanted ions in semiconductor's layer is crucial in order to accurately estimate the ion distribution and concentration in the target substrates. It also gives the predicted number of vacancies and interstitials after the collision events. This is particularly important prior to the ion implantation so as to reduce the defect formation and damage to the target's lattice which subsequently degrade the performance of the device. In this paper, we studied the optimized energy and range of ions implanted silicon in In0.53Ga0.47As film by utilizing the Stopping Range of Ions in Matter (SRIM) simulation. The effects of implantation energy in different thickness are also discussed based on creation of phonons, vacancies and ionization.","PeriodicalId":268203,"journal":{"name":"2014 IEEE International Conference on Semiconductor Electronics (ICSE2014)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124096705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-13DOI: 10.1109/SMELEC.2014.6920858
Iffa Binti Sharuddin, L. Lee
An ultra-low power and area efficient successive approximation register (SAR) analog-to-digital converter (ADC) is presented. To achieve ultra-low power performance, a digital-to-analog converter (DAC) architecture is proposed that combined a 4-bit thermometer coded and a 6-bit C-2C array to form a 10-bit DAC. Thereby, power consumption and area of the design are drastically reduced by virtue of lower switching activity and smaller size capacitor array. Add on to that, the architecture also has better linearity. The proposed 10-bit DAC is designed and simulated in a 0.18 μm CMOS process. Simulation results show that it only consumed 1.74 nW at 1.5 V power supply.
{"title":"An ultra-low power and area efficient 10 bit digital to analog converter architecture","authors":"Iffa Binti Sharuddin, L. Lee","doi":"10.1109/SMELEC.2014.6920858","DOIUrl":"https://doi.org/10.1109/SMELEC.2014.6920858","url":null,"abstract":"An ultra-low power and area efficient successive approximation register (SAR) analog-to-digital converter (ADC) is presented. To achieve ultra-low power performance, a digital-to-analog converter (DAC) architecture is proposed that combined a 4-bit thermometer coded and a 6-bit C-2C array to form a 10-bit DAC. Thereby, power consumption and area of the design are drastically reduced by virtue of lower switching activity and smaller size capacitor array. Add on to that, the architecture also has better linearity. The proposed 10-bit DAC is designed and simulated in a 0.18 μm CMOS process. Simulation results show that it only consumed 1.74 nW at 1.5 V power supply.","PeriodicalId":268203,"journal":{"name":"2014 IEEE International Conference on Semiconductor Electronics (ICSE2014)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129233805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-13DOI: 10.1109/SMELEC.2014.6920866
Ching-Hsiang Hsu, Hsun-Jui Chang, H. Yu, Hong-Quan Nguyen, J. Ma, E. Chang
Au-free, fully Cu-metallized InGaP/InGaAs/Ge triple-junction solar cells using Pd/Ge/Cu as front contact and Pt/Ti/Pt/Cu/Cr as back contact were fabricated and the results are reported for the first time. From the specific contact resistance measurement, these Cu-metallized ohmic contacts have low contact resistance in the order of 10-6 Ω-cm2. AES and TEM results clearly show the formation mechanisms of the Cu-metallization ohmic structures, for Pd/Ge/Cu contact, it was due to the formation of Ge diffusion into the GaAs layer, and for the Pt/Ti/Pt/Cu/Cr contact, it was due to high work function of Pt layer, these copper metallized ohmic contacts were quite stable even after 310 °C annealing. The I-V curves of the Cu-metallized InGaP/InGaAs/Ge triple-junction solar cells showed similar electrical characteristics to the solar cells with Au-metallized triple junction solar cell. Overall, the Pd/Ge/Cu and Pt/Ti/Pt/Cu ohmic contacts have been successfully applied to the InGaP/InGaAs/Ge triple-junction solar cells and demonstrated excellent performance.
{"title":"Gold-free Cu-metallized III-V solar cell","authors":"Ching-Hsiang Hsu, Hsun-Jui Chang, H. Yu, Hong-Quan Nguyen, J. Ma, E. Chang","doi":"10.1109/SMELEC.2014.6920866","DOIUrl":"https://doi.org/10.1109/SMELEC.2014.6920866","url":null,"abstract":"Au-free, fully Cu-metallized InGaP/InGaAs/Ge triple-junction solar cells using Pd/Ge/Cu as front contact and Pt/Ti/Pt/Cu/Cr as back contact were fabricated and the results are reported for the first time. From the specific contact resistance measurement, these Cu-metallized ohmic contacts have low contact resistance in the order of 10-6 Ω-cm2. AES and TEM results clearly show the formation mechanisms of the Cu-metallization ohmic structures, for Pd/Ge/Cu contact, it was due to the formation of Ge diffusion into the GaAs layer, and for the Pt/Ti/Pt/Cu/Cr contact, it was due to high work function of Pt layer, these copper metallized ohmic contacts were quite stable even after 310 °C annealing. The I-V curves of the Cu-metallized InGaP/InGaAs/Ge triple-junction solar cells showed similar electrical characteristics to the solar cells with Au-metallized triple junction solar cell. Overall, the Pd/Ge/Cu and Pt/Ti/Pt/Cu ohmic contacts have been successfully applied to the InGaP/InGaAs/Ge triple-junction solar cells and demonstrated excellent performance.","PeriodicalId":268203,"journal":{"name":"2014 IEEE International Conference on Semiconductor Electronics (ICSE2014)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134258103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-13DOI: 10.1109/SMELEC.2014.6920852
N. Iqbal, M. Baqir, P. Choudhury
Electromagnetic behavior of twisted clad optical fiber structure is investigated under the situation of core section being composed of chiral nihility metamaterial. Twists in the fiber clad are introduced in the form of sheath helical conductor loadings at the core-clad interface. The dispersion relation for the fiber structure is deduced and analyzed (considering low-order sustained hybrid modes) in respect of the effect on the dispersion characteristics due to the alterations in helix pitch angle. It have been found that the fiber structure generally shows decrease in normalized propagation constant with the increase normalized frequency parameter. Also, the dispersion behavior is greatly affected due to the variations in the angle of twists in the helix pitch.
{"title":"Dispersion characteristics of twisted clad chiral nihility fibers","authors":"N. Iqbal, M. Baqir, P. Choudhury","doi":"10.1109/SMELEC.2014.6920852","DOIUrl":"https://doi.org/10.1109/SMELEC.2014.6920852","url":null,"abstract":"Electromagnetic behavior of twisted clad optical fiber structure is investigated under the situation of core section being composed of chiral nihility metamaterial. Twists in the fiber clad are introduced in the form of sheath helical conductor loadings at the core-clad interface. The dispersion relation for the fiber structure is deduced and analyzed (considering low-order sustained hybrid modes) in respect of the effect on the dispersion characteristics due to the alterations in helix pitch angle. It have been found that the fiber structure generally shows decrease in normalized propagation constant with the increase normalized frequency parameter. Also, the dispersion behavior is greatly affected due to the variations in the angle of twists in the helix pitch.","PeriodicalId":268203,"journal":{"name":"2014 IEEE International Conference on Semiconductor Electronics (ICSE2014)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133281014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-13DOI: 10.1109/SMELEC.2014.6920878
S. T. Ten, U. Hashim, F. Malek, W. Liu, K. L. Foo, C. Voon, F. H. Wee, Y. S. Lee, H. Hisham, A. Sudin, M. S. Nur Humaira
Surface acoustic waves (SAW) devices have been initially developed and used for the high-volume low-cost TV component. Due to the ultra-sensitivity to the surface perturbation, SAW based devices have been modified to be sensors. Initially, SAW based sensors were developed for gas detection and recently they have been moving towards biological detection. Shear horizontal surface acoustic wave (SHSAW), one of the SAW based type is most suitable for the application in liquid based condition. Ultra sensitive pathogen sensors are needed to improve the food security and quality of life as well. Hence, the ultra-high sensitive biosensor has been designed in this research towards the low concentration pathogen detection. One of the main SHSAW components is the interdigital transducer (IDT). Currently, there are variety of techniques to fabricate the accurate size electrodes, Electron beam lithography and X-ray lithography. However, these methods are very costly. Therefore, this paper is presenting the more economical fabrication process which is using complementary metal-oxide-semiconductor method to fabricate inter-digital transducers on 640 YX LiNbO3 piezoelectric substrate. Comparisons were made for the theoretical calculation and fabricated measurement resonant frequency of the 3μm, 8 μm, 12 μm, 25 μm and 20μm width IDTs and the differences obtained are less than 5%.
{"title":"Fabrication of a CMOS-compatible surface acoustic wave device for application in pathogen sensing","authors":"S. T. Ten, U. Hashim, F. Malek, W. Liu, K. L. Foo, C. Voon, F. H. Wee, Y. S. Lee, H. Hisham, A. Sudin, M. S. Nur Humaira","doi":"10.1109/SMELEC.2014.6920878","DOIUrl":"https://doi.org/10.1109/SMELEC.2014.6920878","url":null,"abstract":"Surface acoustic waves (SAW) devices have been initially developed and used for the high-volume low-cost TV component. Due to the ultra-sensitivity to the surface perturbation, SAW based devices have been modified to be sensors. Initially, SAW based sensors were developed for gas detection and recently they have been moving towards biological detection. Shear horizontal surface acoustic wave (SHSAW), one of the SAW based type is most suitable for the application in liquid based condition. Ultra sensitive pathogen sensors are needed to improve the food security and quality of life as well. Hence, the ultra-high sensitive biosensor has been designed in this research towards the low concentration pathogen detection. One of the main SHSAW components is the interdigital transducer (IDT). Currently, there are variety of techniques to fabricate the accurate size electrodes, Electron beam lithography and X-ray lithography. However, these methods are very costly. Therefore, this paper is presenting the more economical fabrication process which is using complementary metal-oxide-semiconductor method to fabricate inter-digital transducers on 640 YX LiNbO3 piezoelectric substrate. Comparisons were made for the theoretical calculation and fabricated measurement resonant frequency of the 3μm, 8 μm, 12 μm, 25 μm and 20μm width IDTs and the differences obtained are less than 5%.","PeriodicalId":268203,"journal":{"name":"2014 IEEE International Conference on Semiconductor Electronics (ICSE2014)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132594937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-13DOI: 10.1109/SMELEC.2014.6920819
I. Saad, H. M. Zuhir, C. B. Seng, A. M. Khairul, B. Ghosh, N. Bolong, R. Ismail
This paper venture into prospective ideas of finding viable solution of nanoelectronics device design by an assessment of incorporating vertical impact-ionization MOSFET (IMOS) with strained SiGe technology into a formation of an emerging device structure with elevated performance and reliable outcomes for future bio-based sensor application. Impact Ionization FET biosensors can be extremely promising for applications where ultra-high sensitivity and fast response is desirable. An ultra-low power with low Subthreshold Swing and high breakdown voltage are imperative for ultra-sensitive biosensor. Impact ionization MOSFET (IMOS) is expected to have a subthreshold swing (S) down to 20 mV/dec which is much lower compared to Conventional MOSFET (CMOS). This will eventually enhanced the switching behavior of the transistor and enhancing its electrical performance and response time particularly when scaled down into nanometre regime. However, vertical IMOS experience parasitic bipolar transistors (PBT) effect and low breakdown voltage. Parasitic Bipolar Transistor effect is a phenomenon where the MOSFET act as a minority carrier device like BJT instead of majority carrier device. This is not favorable for any power device or sensor. Dielectric Pocket (DP) is believed to be able to minimize the PBT effect while improving the performance of the device. Eventually, this device will prolong the increase density of transistor in a chip for future application of biosensor nanoelectronics.
{"title":"Characterization of vertical strained SiGe impact ionization MOSFET for ultra-sensitive biosensor application","authors":"I. Saad, H. M. Zuhir, C. B. Seng, A. M. Khairul, B. Ghosh, N. Bolong, R. Ismail","doi":"10.1109/SMELEC.2014.6920819","DOIUrl":"https://doi.org/10.1109/SMELEC.2014.6920819","url":null,"abstract":"This paper venture into prospective ideas of finding viable solution of nanoelectronics device design by an assessment of incorporating vertical impact-ionization MOSFET (IMOS) with strained SiGe technology into a formation of an emerging device structure with elevated performance and reliable outcomes for future bio-based sensor application. Impact Ionization FET biosensors can be extremely promising for applications where ultra-high sensitivity and fast response is desirable. An ultra-low power with low Subthreshold Swing and high breakdown voltage are imperative for ultra-sensitive biosensor. Impact ionization MOSFET (IMOS) is expected to have a subthreshold swing (S) down to 20 mV/dec which is much lower compared to Conventional MOSFET (CMOS). This will eventually enhanced the switching behavior of the transistor and enhancing its electrical performance and response time particularly when scaled down into nanometre regime. However, vertical IMOS experience parasitic bipolar transistors (PBT) effect and low breakdown voltage. Parasitic Bipolar Transistor effect is a phenomenon where the MOSFET act as a minority carrier device like BJT instead of majority carrier device. This is not favorable for any power device or sensor. Dielectric Pocket (DP) is believed to be able to minimize the PBT effect while improving the performance of the device. Eventually, this device will prolong the increase density of transistor in a chip for future application of biosensor nanoelectronics.","PeriodicalId":268203,"journal":{"name":"2014 IEEE International Conference on Semiconductor Electronics (ICSE2014)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125222746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-13DOI: 10.1109/SMELEC.2014.6920897
H. Hashim, S. S. Shariffudin, A. Khairuddin, M. Sarah, M. Rusop
Light-emitting diode (LED) applications consist of various materials. One of the materials used is polymer. In this study, MEH-PPV known as poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1, 4-phenylenevinylene] was used. The objective of this paper is to characterize the electrical and optical properties of MEH-PPV thin film by using sol-gel method. The scope is to study only the MEH-PPV thin film without implementation to any device. The MEH-PPV thin film thicknesses were varied from 10 to 100 nm. The experiment was started by stirring the sol-gel solution with toluene. The spin-coating technique was used to deposit the MEH-PPV thin film on a glass substrate. All samples were characterized using Atomic Force Microscopy (AFM), Surface Profiler, Two-point Probe, Raman PL Dispersive and UV-Vis Spectroscopy for the surface morphologies, thin film thickness, electrical and optical properties respectively. From the current-voltage (I-V) measurement, it show that symmetrical line plotted at low-voltage ranges. Moreover, the calculated conductivity was inversely proportional with the thin film thickness. The results from photoluminescence (PL) spectra showed that the intensity reached optimum peak at 38nm thickness and quenched for other samples. At 108 nm of thickness, absorption reached the highest peak compared to other samples of different thickness. The film was non-uniformed for the thickness at 134 nm, due to aggregation phenomenon.
{"title":"Electrical and optical properties characterization of MEH-PPV thin film using sol-gel method","authors":"H. Hashim, S. S. Shariffudin, A. Khairuddin, M. Sarah, M. Rusop","doi":"10.1109/SMELEC.2014.6920897","DOIUrl":"https://doi.org/10.1109/SMELEC.2014.6920897","url":null,"abstract":"Light-emitting diode (LED) applications consist of various materials. One of the materials used is polymer. In this study, MEH-PPV known as poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1, 4-phenylenevinylene] was used. The objective of this paper is to characterize the electrical and optical properties of MEH-PPV thin film by using sol-gel method. The scope is to study only the MEH-PPV thin film without implementation to any device. The MEH-PPV thin film thicknesses were varied from 10 to 100 nm. The experiment was started by stirring the sol-gel solution with toluene. The spin-coating technique was used to deposit the MEH-PPV thin film on a glass substrate. All samples were characterized using Atomic Force Microscopy (AFM), Surface Profiler, Two-point Probe, Raman PL Dispersive and UV-Vis Spectroscopy for the surface morphologies, thin film thickness, electrical and optical properties respectively. From the current-voltage (I-V) measurement, it show that symmetrical line plotted at low-voltage ranges. Moreover, the calculated conductivity was inversely proportional with the thin film thickness. The results from photoluminescence (PL) spectra showed that the intensity reached optimum peak at 38nm thickness and quenched for other samples. At 108 nm of thickness, absorption reached the highest peak compared to other samples of different thickness. The film was non-uniformed for the thickness at 134 nm, due to aggregation phenomenon.","PeriodicalId":268203,"journal":{"name":"2014 IEEE International Conference on Semiconductor Electronics (ICSE2014)","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127089320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-13DOI: 10.1109/SMELEC.2014.6920874
S. R. Kasjoo, M. M. Ramli, M. Zakaria, M. Arshad, R. Ayub, R. A. Rahim, U. Hashim
In this work, a back-gated field-effect device based on an exfoliated thin film of few-layer graphene (FLG) has been fabricated and some of its properties were characterized. The estimated hole mobility of the FLG film, extracted from the device transconductance, was approximately 843 cm2V-1s-1 which was lower than the typical reported values. The reasons for the lower mobility were briefly discussed in terms of charged impurity density, and contact resistance between FLG film and metal. The use of mechanical exfoliation method in producing thin films of FLG, which is cheap, fast and simple, can also be exploited in the development of other graphene-based devices.
{"title":"A field-effect device based on an exfoliated thin film of few-layer graphene","authors":"S. R. Kasjoo, M. M. Ramli, M. Zakaria, M. Arshad, R. Ayub, R. A. Rahim, U. Hashim","doi":"10.1109/SMELEC.2014.6920874","DOIUrl":"https://doi.org/10.1109/SMELEC.2014.6920874","url":null,"abstract":"In this work, a back-gated field-effect device based on an exfoliated thin film of few-layer graphene (FLG) has been fabricated and some of its properties were characterized. The estimated hole mobility of the FLG film, extracted from the device transconductance, was approximately 843 cm2V-1s-1 which was lower than the typical reported values. The reasons for the lower mobility were briefly discussed in terms of charged impurity density, and contact resistance between FLG film and metal. The use of mechanical exfoliation method in producing thin films of FLG, which is cheap, fast and simple, can also be exploited in the development of other graphene-based devices.","PeriodicalId":268203,"journal":{"name":"2014 IEEE International Conference on Semiconductor Electronics (ICSE2014)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116259226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-13DOI: 10.1109/SMELEC.2014.6920844
M. A. Mohamed, B. Majlis, M. Ani
Electron state transition of deep level point defects in a semiconductor crystal was studied. Low-temperature grown GaAs produced excess antisite As (AsGa) which produces localized spin when doped with Be. A nearly abrupt decrease of 1.7% of the resistance is detected at a temperature around 4 K which is consistent with abrupt decrease of magnetization. These observations are explained as a result of cooperative transition of electron states of AsGa defects. First-principal calculations of the electron state of an AsGa atom with a shallow acceptor Be show that at the transition an AsGa+ ion is displaced to the interstitial site and becomes a neutral atom and finally results in formation of a hole producing enhancement in conductivity.
{"title":"Electronic state transition in cooperatively interacting point-defects in semiconductor crystals","authors":"M. A. Mohamed, B. Majlis, M. Ani","doi":"10.1109/SMELEC.2014.6920844","DOIUrl":"https://doi.org/10.1109/SMELEC.2014.6920844","url":null,"abstract":"Electron state transition of deep level point defects in a semiconductor crystal was studied. Low-temperature grown GaAs produced excess antisite As (AsGa) which produces localized spin when doped with Be. A nearly abrupt decrease of 1.7% of the resistance is detected at a temperature around 4 K which is consistent with abrupt decrease of magnetization. These observations are explained as a result of cooperative transition of electron states of AsGa defects. First-principal calculations of the electron state of an AsGa atom with a shallow acceptor Be show that at the transition an AsGa+ ion is displaced to the interstitial site and becomes a neutral atom and finally results in formation of a hole producing enhancement in conductivity.","PeriodicalId":268203,"journal":{"name":"2014 IEEE International Conference on Semiconductor Electronics (ICSE2014)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116535142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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