光子晶体在Si基发光材料中的应用研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

Ge/Si纳米岛材料与器件研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

Si 基ZnO 材料MOCVD 生长及物性研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

GaN 基异质结中的极化效应及Si 衬底GaN 生长研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

Si基量子级联激光器能带设计和材料生长

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

Si(111)衬底上GaN 外延的MOCVD 生长及其应力研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

Si 基及图形衬底GaN 异质外延研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

Si 共掺杂和高温退火对(Ga,Mn)As 结构和磁性质的影响

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

大直径SI-GaAs 单晶的VGF 生长技术和材料性质研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

Si 基波导耦合滤波特性研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

Si(111)衬底上GaN薄膜的生长及应变调控研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

Study of GaN epilayers growth on freestanding Si cantilevers

Five-micron thick freestanding Si cantilevers were fabricated on bulk Si (1 1 1) substrates with surface/bulk micromachining (SBM) process. Then 1-mu m thick GaN layers were deposited on the Si cantilevers by metal-organic chemical vapor deposition (MOCVD). Epilayers on cantilever areas were obtained crack-free, and the photoluminescence (PL) spectra verified the stress reduction and better material quality in these suspended parts of GaN. Back sides of the cantilevers were also covered with GaN layers, which prevented the composite beams from bending dramatically. This paper had proved the feasibility of integrating high-quality GaN epilayers with Si micromechanical structures to realize GaN-based micro electro-mechanical system (MEMS). (C) 2009 Elsevier Ltd. All rights reserved.

Quantum Mechanical Study on Tunnelling and Ballistic Transport of Nanometer Si MOSFETs

Using self-consistent calculations of million-atom Schrodinger-Poisson equations, we investigate the I-V characteristics of tunnelling and ballistic transport of nanometer metal oxide semiconductor field effect transistors (MOSFET) based on a full 3-D quantum mechanical simulation under nonequilibtium condition. Atomistic empirical pseudopotentials are used to describe the device Hamiltonian and the underlying bulk band structure. We find that the ballistic transport dominates the I-V characteristics, whereas the effects of tunnelling cannot be neglected with the maximal value up to 0.8mA/mu m when the channel length of MOSFET scales down to 25 nm. The effects of tunnelling transport lower the threshold voltage V-t. The ballistic current based on fully 3-D quantum mechanical simulation is relatively large and has small on-off ratio compared with results derived from the calculation methods of Luo et al.

Influence of AlN buffer layer thickness on structural properties of GaN epilayer grown on Si (111) substrate with AlGaN interlayer

We present the growth of GaN epilayer on Si (111) substrate with a single AlGaN interlayer sandwiched between the GaN epilayer and AlN buffer layer by using the metalorganic chemical vapour deposition. The influence of the AlN buffer layer thickness on structural properties of the GaN epilayer has been investigated by scanning electron microscopy, atomic force microscopy, optical microscopy and high-resolution x-ray diffraction. It is found that an AlN buffer layer with the appropriate thickness plays an important role in increasing compressive strain and improving crystal quality during the growth of AlGaN interlayer, which can introduce a more compressive strain into the subsequent grown GaN layer, and reduce the crack density and threading dislocation density in GaN film.

Au@Si-n: Growth behavior, stability and electronic structure

The configurations, stability, and electronic structure of AuSin (n = 1-16) clusters have been investigated within the framework of the density functional theory at the B3PW91/LanL2DZ and PW91/DNP levels. The results show that the Au atom begins to occupy the interior site for cages as small as Si-11 and for Si-12 the Au atom completely falls into the interior site forming Au@Si-12 cage. A relatively large embedding energy and small HOMO-LUMO gap are also found for this Au@Si-12 structure indicating enhanced chemical activity and good electronic transfer properties. All these make Au@Si-12 attractive for cluster-assembled materials.