半导体SiC材料的外延生长

ＳｉＣ具有禁带宽度大、热导率高、电子的饱和漂移速度大、临界击穿电场高和介电常数低等特点，在高频、大功率、耐高温、抗辐照的半导体器件及紫外探测器和短波发光二极管等方面具有广泛的应用前景。本文简要介绍ＳｉＣ半导体材料的液相外延、化学气相和分子束外延生长的概况及生长过程中杂质的控制。     

具有宽带响应的GaAs／AlGaAs多量子阱红外探测器

报道具有宽带响应的130元线列GaAs/AlGaAs多量子阱红外探测器的研究进展.通过表面光栅耦合,采用垂直入射的工作模式,在T=80K时测得器件探测率的光谱响应曲线的半峰宽为4.3μm.在λ_p=9.5μm时的峰值探测率为4.89×10~9cmHz~(1/2)/W,电压响应率为2.89×10~4V/W.     

The effect of δ-doping and modulation-doping on Si-doped high Al content n-AlxGa1-xN grown by MOCVD

The effect of periodic delta-doping and modulation-doping on high Al content n-Al_xGa_1-xN（x = 0.55） epilayers grown by MOCVD has been investigated.Measured by XRD,AFM,contactless sheet resistance, and Hall-effect tests,δ-doped and modulation-doped n-Al_xGa_1-xN have better crystal quality,surface morphology and electrical properties as compared with uniformly-doped n-Al_xGa_1-xN.These improvements are attributed to the SiN_x growth mask induced by 5-doping layers and the dislocation-blocking effect induced by both growth techniques.In addition,due to the broadened doping profile ascribed to enhanced dopant diffusion at high growth temperatures（1150℃） of n-Al_0.55Ga_0.45N,modulation-doped n-Al_0.55Ga_0.45N has similar properties asδ-doped n-Al_0.55Ga_0.45N.     

利用水平热壁CVD法生长的3C-SiC/Si的均匀性

利用新改进的水平低压热壁CVD设备,改变生长时的压力和H2流速,在50mm的Si(100)和(111)衬底上获得了3C-SiC外延膜,并对外延膜的结构均匀性、电学均匀性和厚度均匀性进行了分析.X射线衍射图中出现了强的3C-SiC的特征峰,其中3C-SiC的(200)和(111)峰的半高宽分别为0.41°和0.21°.3C-SiC外延膜方块电阻的均匀性最好可达2.15%.厚度均匀性可达±5.7%(σ/mean值).     

采用AlN缓冲层在Si(111)衬底上生长GaN的形貌

针对Si衬底上生长GaN具有的特有形貌进行了研究,分析采用扫描电镜(SEM)、X射线能谱仪(EDS)、原子力显微镜(AFM)等手段,研究了使用AlN作为缓冲层的GaN的生长模式、缺陷形成机理、应力释放机制.并且发现缓冲层厚度和外延层生长温度对裂纹和表面缺陷的形成有很大的影响.     

高阻GaN薄膜电阻率测量

建立了绝缘电阻大于1013Ω和温度起伏小于0.1℃的高阻GaN薄膜电阻率装置,并简述了其测量电阻率的原理.研究了环境温度、湿度、漏电流、数据读取时间、测量电压、样品尺寸等因素对电阻率与迁移率的影响,并讨论了各种因素所引起的测量误差.     

6kW高效、高功率全固态连续波激光器

全固态激光器(DPSSL)具有体积小、重量轻、效率高、性能稳定、可靠性好、寿命长、光束质量高等优点,近年来已成为激光学科的重点发展方向之一,高功率全固态激光器在工业加工、军事和科研等领图1高功率全固态激光器光路图Fig.1Schematic diagramof the high power DPSSL域有十分重要的用途。本实验利用自主研制的高功率激光头,使用Nd∶YAG晶体棒作为增益介质,采用图1所示的三棒串接获得高功率1064nm连续波激光输出。该激光器经过专家测试,输出功率达6.03kW,光-光转换效率超过50%。6kW高效、高功率全固态连续波激光器$中国科学院半导…     

Si衬底上SiC薄膜的快速生长

用垂直式低压化学气相沉积(LPCVD)系统,在(111)和(100)Si衬底上快速外延生长了SiC.用Nomarski光学显微镜和X射线衍射(XRD)分析了SiC外延膜.探讨了生长速度与反应气体流量的关系,HCl在反应过程中的作用机理,以及在快速生长条件下外延膜的结晶和取向关系.     

基于Mg掺杂有机受体薄膜的有机发光二极管

采用Mg掺杂有机受体材料3,4,9,10 perylenetetracarboxylic dianhydride(PTCDA)做为电子注入层,Ag做为阴极,制备了一种新型的有机发光二极管.同传统的Mg:Ag合金电极相比,PTCDA:Mg/Ag对Alq3的电子注入能力略有提高,但是由于Ag在可见光范围内的反射能力高于Mg:Ag合金,相应器件的效率提高了近40%.在无定形的PTCDA:Mg薄膜中,Mg和PTCDA被认为通过弱关联作用形成一种络合物.     

Evaluation of light extraction efficiency for the light-emitting diodes based on the transfer matrix formalism and ray-tracing method

The internal quantum efficiency (IQE) of the light-emitting diodes can be calculated by the ratio of the external quantum efficiency (EQE) and the light extraction efficiency (LEE). The EQE can be measured experimentally, but the LEE is difficult to calculate due to the complicated LED structures. In this work, a model was established to calculate the LEE by combining the transfer matrix formalism and an in-plane ray tracing method. With the calculated LEE, the IQE was determined and made a good agreement with that obtained by the ABC model and temperature-dependent photoluminescence method. The proposed method makes the determination of the IQE more practical and conventional.