光子晶体对nc-Ge/Si岛发光增强的模拟

在Si基集成光电子学的发展中,高效的Si基光源是人们不懈追求的目标.但是Si材料的间接带隙特性导致其发光效率低,更谈不上受激发射.于是人们探索了多种Si基材料体系来提高Si材料的发光效率,并在不同程度上取得了重要的进展.在众多的Si基发光材料体系中,Ge/Si量子点材料,不仅生长工艺与标准的CMOS工艺有很好的兼容性,而且发光波长能够覆盖重要的光通信波段即1.3～1.55 μm,因此成为实现Si基发光器件的重要途径之一.但是目前这种材料的发光效率仍很低,所以提高其发光效率自然成为人们关注的焦点.如果将光子晶体引入到nc-Ge/Si材料中,它不仅可以改变材料本身的自发发射特性,而且可以改变发射的光子的提取效率,从而使材料的发光效率得到增强.提出了在Ge/Si量子点材料中引入光子晶体结构来提高其发光效率,包括光子晶体点缺陷腔结构和带边模式工作的完整光子晶体结构,并从理论上分析了发光效率提高的原理.针对发光波长在1.5 μm附近的材料结构,模拟出了相应的光子晶体的结构参数.从模拟结果可以看出,对于缺陷腔的光子晶体结构,采用单点缺陷微腔很好地实现了单模运作,但是微腔内有源材料的体积很小,因此得到的发光效率很低.而采用耦合缺陷腔的结构和H2腔都增加了腔内有源区的体积.但是耦合腔与H2腔相比,谐振腔模减少,主谐振模式的峰值强度增加,更容易实现单模发光.因而更适用于提高nc-Ge/Si的发光效率.而带边模式工作的光子晶体结构,尺寸较大,不需引入缺陷,工艺上更容易实现.

Low -temperature preparation of ZnO films on Si substrates by MOCVD

ZnO films were deposited on Si（100） substrates at 300℃ by metal - organic chemical vapor deposition（MOCVD）. The effect of different ratios of DEZn to N2O on crystal quality was analyzed. It is found that the optimum ratio of DEZn to N2O is 2.1. And in this optimum growth condition, X - ray diffraction （XRD） and scanning probe morphology （SPM） images indicate that the films grow along the c - axis orientation. ZnO film exhibits a strong UV optical absorption near 388 nm. And the optical absorbance is close to zero,that indicates nearly 100% optical transparence. Photoluminescence （PL） spectrum shows only strong near - band - edge emissions with little or no deep - level emission related to defects. The full - width at half - maximum （FWHM） of the ultraviolet emission peak is 80meV. The results indicate that better crystal quality can be obtained.

Growth of near planar Si0.5Ge0.5 epitaxial layers directly on Si substrate by UHV/CVD at 500℃

The relationship between Ge content of Si1-xGex layers and growth conditions was investigated via UHV/CVD system at relative low temperature of 500℃. Si1-xGex layers were in a metastable state in this case. 10-period strained 3.0 nm- Si0.5Ge0.5/3.4 nm- Si multi quantum wells were obtained directly on Si substrate. Raman Measurement, high resolution electron microscopy and photoluminescence were used to characterize the structural and optical properties. It is found that such relative thick Si0.5Ge0.5/Si multi quantum wells are still near planar and free of dislocations, that makes it exploit applications to electrical and optical devices.

纳米Si镶嵌SiO2薄膜的发光与非线性光学特性的应用

采用射频磁控溅射技术和热退火处理制备了纳米Si镶嵌SiO2薄膜，在室温下观察到光致发光现象，峰值分别位于360，430和835nm，结合吸收谱、光致发光激发谱和X射线衍射分析讨论了发光机理．利用纳米Si镶嵌SiO2薄膜的非线性光学特性可作为可饱和吸收体，在Nd

带有Bragg反射镜的谐振腔增强型Si光电探测器

采用电子束蒸发和键合技术，制作了具有高反射率的、表面为薄层单晶Si的分布Bragg反射器。用标准光刻工艺在单晶Si薄层上制作出窄带谐振腔增强型（RCE）金属一半导体一金属（MSM）光电探测器，响应峰值波长分别在836、900、965和1030nm处，其中在900nm处峰值半高宽为18nm。该器件具有波长选择特性，可有效抑制相邻频道间的串扰，而且容易制成集成面阵。

Design and Fabrication of Power Si1-xGex/Si Heterojunction Bipolar Transistor for Wireless Power Amplifier Applications

A multi-finger structure power SiGe HBT device （with an emitter area of about 166μm^2） is fabricated with very simple 2μm double-mesa technology. The DC current gain β is 144.25. The B-C junction breakdown voltage reaches 9V with a collector doping concentration of 1 × 10^17cm^-3 and a collector thickness of 400nm. Though our data are influenced by large additional RF probe pads, the device exhibits a maximum oscillation frequency fmax of 10.1GHz and a cut-off frequency fτ of 1.8GHz at a DC bias point of IC=10mA and VCE = 2.5V.

在复合衬底γ-Al2O3／Si（001）上生长GaN

采用分子束外延（MBE）生长方法，使用γ-Al2O3材料作为新型过渡层，在Si（001）衬底上获得了没有裂纹的GaN外延层，实验结果表明使用γ-Al2O3过渡层有效地缓解了外延层中的应力．通过生长并测试分析几种不同结构的外延材料，研究了复合衬底γ-Al2O3／Si（001）生长GaN情况，得到了六方相GaN单晶材料，实现了GaNC面生长．预铺薄层Al及高温AIN层可以提高GaN晶体质量，低温AIN缓冲层可以改善GaN表面的粗糙度．为解决Si（001）衬底上GaN的生长问题提供了有益的探索。

GaAs／Si／AlAs异质结的DLTS实验研究

利用深能级瞬态谱（DLTS）技术研究了Si夹层和GaAs层不同生长温度对GaAs／AlAs异质结晶体品质的影响。发现Si夹层的引入并没有引起明显深能级缺陷，而不同温度下生长的GaAs／Si／AlAs异质结随着温度的降低，深能级缺陷明显增加，并进行了分析，得到深能级是由Ga空位引起的，在600℃时生长的晶体质量最佳。

Si上外延的n型3C-SiC欧姆接触研究

用LPCVD在si（111）上异质外延了n型3C-SiC，并在所外延的3C-SiC上蒸发Au／Ti，通过不同温度下的RTA（快速热退火）形成欧姆接触。用两种不同的传输线模型对Ti／3C-SiC欧姆接触的ρc（比接触电阻率）进行测量，在750℃退火后Ti／3C-SiC的ρc达到了最低值为3．68×10^-5Ω·cm^2这满足了应用的要求。AES分析结果还表明由于Ti的氧化，更高温度下的退火会使ρc增大。

带隙法测定SiGe／Si材料的应变状态

从固体模型理论的结果出发，计算了生长于Si（100）衬底上x值小于0．85的Si1-xGex合金材料（能带结构为类蛳结构）的间接带隙与应变的关系，结果表明，应变的SiGe材料的带隙和完全弛豫状态下材料的带隙之差与应变呈线性关系．基于这一结果，提出了用测量带隙来间接测定SiGe／Si应变状态的方法．用带隙法和x射线双晶衍射法测量了不同应变状态下的SiGe／Si多量子阱材料的应变弛豫度，两者可以较好的符合，表明带隙法测量SiGe应变弛豫度是可行的．

Si基热光可调谐窄带平顶滤波器

利用Si基键合技术、台阶型F-P腔结构以及Si良好的热光效应，研制了一种新型全Si基的热光调谐窄带平顶滤波器．器件的平顶宽度为2nm，3dB带宽为4．4nm，自由谱宽约为8．5nm，在外加电场作用下，共振峰红移3．3nm．

Effects of Thickness on Properties of ZnO Films Grown on Si by MOCVD

High quality ZnO films are successfully grown on Si（100） substrates by metal-organic chemical vapor deposition at 300℃. The effects of the thickness of the ZnO films on crystal structure, surface morphology,and optical properties are investigated using X-ray diffraction, scanning probe microscopy,and photoluminescence spectra, respectively. It is shown that the ZnO films grown on Si substrates have a highly-preferential C-axis orientation,but it is difficult to obtain the better structural and optical properties of the ZnO films with the increasing of thickness. It is maybe due to that the grain size and the growth model are changed in the growth process.

LPCVD Growth of 3C-SiC on Si Mesas and SiO2/Si Substrates for MEMS Applications

This paper presents the development of LPCVD growth of 3C-SiC thin films grown on Si mesas and thermally oxidized SiO2 masks over Si with an area of 150 × 100μm^2 and SiO2/Si substrates. The growth has been performed via chemical vapor deposition using SiH4 and C2H4 precursor gases with carrier gas of H2. 3C-SiC films on these substrates were characterized by optical microscopy, X-ray diffraction （ XRD ）, X-ray photoelectron spectroscopy （ XPS ）, scanning electron microscopy （SEM） and room temperature Hall effect measurements. It is shown that there were no voids at the interface between 3C-SiC and SiO2.

16×0．8nm Si基SiO2阵列波导光栅设计、制备及测试

叙述了一个完整的16通道硅基二氧化硅阵列波导光栅(AWG)的设计、制备及测试过程。通道间隔为0．8nm(100GHz)，解复用器的插入损耗为16．8dB，其中材料损耗为11．95dB，相邻通道串扰小于一17dB，通道插损非均匀性小于2．2dB。

p型纳米硅与a-Si∶H不锈钢底衬nip太阳电池

报道了选用厚度为0．05mm的不锈钢箔作衬底，B掺杂P型氢化纳米硅作窗口层，制备成功开路电压和填充因子分别达到0．90V和0．70的nip非晶硅基薄膜单结太阳电池．UV-VIS透射谱和微区Raman谱证实所用p层具有典型氢化纳米硅的宽能隙和含有硅结晶颗粒的微结构特征．明确指出导致这种氢化纳米硅能隙展宽的物理机制是量子尺寸效应．