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Surface Roughness of SiGe/Si(110) Formed by Stress-Induced Twins and the Solution to Produce Smooth Surface  [PDF]
Junji Yamanaka, Mai Shirakura, Chiaya Yamamoto, Naoto Utsuyama, Kei Sato, Takane Yamada, Kosuke O. Hara, Keisuke Arimoto, Kiyokazu Nakagawa
Journal of Materials Science and Chemical Engineering (MSCE) , 2018, DOI: 10.4236/msce.2018.61004
Abstract:
Lattice-strained Si thin films grown onto SiGe(110)/Si(110) are attracting because of their potential to realize high-speed transistors. In this study we observe surface morphology of Si/SiGe/Si(110) using scanning electron microscopy and we also observe microstructure of the identical position using cross-sectional transmission electron microscopy. These results reveal that crossing of stress-induced twins causes remarkable surface roughness. We propose using vicinal substrate to avoid this phenomenon and our successive experimental results are shown in this paper.
Characterization of Nanocrystalline SiGe Thin Film Solar Cell with Double Graded-Dead Absorption Layer
Chao-Chun Wang,Dong-Sing Wuu,Shui-Yang Lien,Yang-Shih Lin,Chueh-Yang Liu,Chia-Hsum Hsu,Chia-Fu Chen
International Journal of Photoenergy , 2012, DOI: 10.1155/2012/890284
Abstract: The nanocrystalline silicon-germanium (nc-SiGe) thin films were deposited by high-frequency (27.12 MHz) plasma-enhanced chemical vapor deposition (HF-PECVD). The films were used in a silicon-based thin film solar cell with graded-dead absorption layer. The characterization of the nc-SiGe films are analyzed by scanning electron microscopy, UV-visible spectroscopy, and Fourier transform infrared absorption spectroscopy. The band gap of SiGe alloy can be adjusted between 0.8 and 1.7 eV by varying the gas ratio. For thin film solar cell application, using double graded-dead i-SiGe layers mainly leads to an increase in short-circuit current and therefore cell conversion efficiency. An initial conversion efficiency of 5.06% and the stabilized efficiency of 4.63% for an nc-SiGe solar cell were achieved.
Influence of Heterojunction Position on SiGe HBTs with Graded BC Junctions
异质结位置对缓变集电结SiGe HBT性能的影响

Luo Rui,Zhang Wei,Fu Jun,Liu Daoguang,Yan Liren,
雒睿
,张伟,付军,刘道广,严利人

半导体学报 , 2008,
Abstract: The influence of a heterojunction in the vicinity of a graded BC junction on the performance of npn SiGe HBTs is studied.SiGe HBTs differing only in heterojunction position in the vicinity of a graded BC junction are simulated by means of 2D Medici software for DC current gain and frequency characteristics.In addition,the simulated DC current gains and cut-off frequencies are compared at different collector-emitter bias voltages.Through the simulation results,both DC and HF device performance are found to be strongly impacted by degree of confinement of the neutral base in the SiGe layer, even in the absence of a conduction band barrier.This conclusion is of significance for designing and analyzing SiGe HBTs.
System-on-Chip 36.8 GHz Radiometer for Space-Based Observation of Solar Flares: Feasibility Study in 0.25 μM SiGe BiCMOS Technology
Luca Aluigi;Luca Roselli;Stephen M. White;Federico Alimenti
PIER , 2012, DOI: 10.2528/PIER12061101
Abstract: This paper deals with a feasibility study for a System-on-Chip (SoC) mmwave radiometer devoted to space-based observation of solar flares and operating in the Ka-band. The radiometer has been designed in 250 nm SiGe BiCMOS process. The circuit integrates a three stages differential LNA with 37.2 dB gain and 4.8 dB noise figure at 36.8 GHz and a differential square-law detector based on HBTs, featuring a 96 mV/μW responsivity. The full radiometer achieves, potentially, a NETD of 0.1 K for 1 s integration time in Dicke mode. This work represents the first study of such an integrated instrument for Ka-band space-based observation of solar flares.
ELECTRO-LUMINESCENCE AND PHOTO-LUMINESCENCE FROM STRAINED SiGe/Si QUANTUM WELL

DONG WEN-FU,YANG QIN-QING,LI JIAN,WANG QI-MING,CHUI QIAN,ZHOU JUN-MING,HUANG QI,

中国物理 B , 1996,
Abstract: Photo-luminescence and electro-luminescence from step-graded index SiGe/Si quantum well grown by molecular beam epitaxy is reported. The SiGe/Si step-graded index quantum well structure is beneficial to the enhancing of electro-luminescence. The optical and electrical properties of this structure are discussed.
Effects of Interface Disorder on Valley Splitting in SiGe/Si/SiGe Quantum Wells  [PDF]
Zhengping Jiang,Neerav Kharche,Timothy Boykin,Gerhard Klimeck
Physics , 2011, DOI: 10.1063/1.3692174
Abstract: A sharp potential barrier at the Si/SiGe interface introduces valley splitting (VS), which lifts the 2-fold valley degeneracy in strained SiGe/Si/SiGe quantum wells (QWs). This work examines in detail the effects of Si/SiGe interface disorder on the VS in an atomistic tight binding approach based on statistical sampling. VS is analyzed as a function of electric field, QW thickness, and simulation domain size. Strong electric fields push the electron wavefunctions into the SiGe buffer and introduce significant VS fluctuations from device to device. A Gedankenexperiment with ordered alloys sheds light on the importance of different bonding configurations on VS. We conclude that a single SiGe band offset and effective mass cannot comprehend the complex Si/SiGe interface interactions that dominate VS.
Thermopower-enhanced efficiency of Si/SiGe ballistic rectifiers  [PDF]
D. Salloch,U. Wieser,U. Kunze,T. Hackbarth
Physics , 2009, DOI: 10.1063/1.3140439
Abstract: Injection-type ballistic rectifiers on Si/SiGe are studied with respect to the influence of gate voltage on the transfer resistance RT (output voltage divided by input current) for different positions of a local gate electrode. The rectifiers are trifurcated quantum wires with straight voltage stem and oblique current-injecting leads. Depending on the gate configuration, thermopower contributions arise from nearly-pinched stem regions which either cancel each other or impose upon the ballistic signal with same or opposite polarity. At best, this enhances RT to a maximum value of 470 Ohm close to threshold voltage.
Graded Rings and Graded Grothendieck Groups  [PDF]
Roozbeh Hazrat
Mathematics , 2014,
Abstract: This monograph is devoted to a comprehensive study of graded rings and graded K-theory. A bird's eye view of the graded module theory over a graded ring gives an impression of the module theory with the added adjective "graded" to all its statements. Once the grading is considered to be trivial, the graded theory reduces to the usual module theory. So from this perspective, the graded module theory can be considered as an extension of the module theory. However, one aspect that could be easily missed from such a panoramic view is that, the graded module theory comes equipped with a shifting, thanks to being able to partition the structures and rearranging these partitions. This adds an extra layer of structure (and complexity) to the theory. An sparkling example of this is the theory of graded Grothendieck groups, K^{gr}_0, which is the main focus of this monograph. Whereas the usual K_0 is an abelian group, thanks to the shiftings, K^{gr}_0 has a natural Z[\Gamma]-module structure, where \Gamma is the graded group. As we will see throughout this note, this extra structure carries a substantial information about the graded ring.
On the graded center of graded categories  [PDF]
Vladimir Turaev,Alexis Virelizier
Mathematics , 2012,
Abstract: We study the G-centers of G-graded monoidal categories where G is an arbitrary group. We prove that for any spherical G-fusion category C over an algebraically closed field such that the dimension of the neutral component of C is non-zero, the G-center of C is a G-modular category. This generalizes a theorem of M. M\"uger corresponding to G=1. We also exhibit interesting objects of the G-center.
Design of the muscles in motion study: a randomized controlled trial to evaluate the efficacy and feasibility of an individually tailored home-based exercise training program for children and adolescents with juvenile dermatomyositis
G. Esther A. Habers, Marco van Brussel, Anneli C Langbroek-Amersfoort, Annet van Royen, Tim Takken
BMC Musculoskeletal Disorders , 2012, DOI: 10.1186/1471-2474-13-108
Abstract: Subjects (n?=?30) will include 8–18?year olds diagnosed with JDM. The intervention consists of an individually tailored 12-weeks home-based exercise training program in which interval training on a treadmill is alternated with strength training during each session. The program is based on previous literature and designed with a defined frequency, intensity, time, and type of exercise (FITT principles). Primary outcome measures include aerobic exercise capacity, isometric muscle strength, and perception of fatigue. The study methodology has been conceived according to the standards of the CONSORT guidelines. The current study will be a multi-center (4 Dutch University Medical Centers) RCT, with the control group also entering the training arm directly after completion of the initial protocol. Randomization is stratified according to age and gender.The current study will provide evidence on the efficacy and feasibility of an individually tailored 12-week home-based exercise training program in youth with JDM.Medical Ethics Committee of the University Medical Center Utrecht, the Netherlands: 11–336; Netherlands Trial Register (NTR): NTR 3184.
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