Metalorganic Chemical Vapor Deposition of GaNAs Alloy Using Dimethylhydrazine as Nitrogen Precursor

GaNAs alloy is grown by metalorganic chemical vapor deposition (MOCVD) using dimethylhydrazine (DMHy) as the nitrogen precursor. High-resolution X-ray diffraction (HRXRD) and secondary ion mass spectrometry (SIMS) are combined in determining the nitrogen contents in the samples. Room temperature photoluminescence (RTPL) measurement is also used in characterizing. The influence of different Ga precursors on GaNAs quality is investigated. Samples grown with triethylgallium (TEGa) have better qualities and less impurity contamination than those with trimethylgallium (TMGa). Nitrogen content of 5.688% is achieved with TEGa. The peak wavelength in RTPL measurement is measured to be 1278.5nm.

室温铁磁性半导体Mn_xGa_(1-x)Sb

采用离子注入、离子沉积及后期退火方法制备了稀磁半导体单晶Mn_xGa_(1-x)Sb，在室温下（300 K）获得了单晶的磁滞回线。用X射线衍射方法分析了铁磁性半导体单晶Mn_xGa_(1-x)Sb的结构，用电化学C-V法分析了单晶的载流子浓度分布。由X射线衍射得知，Mn_xGa_(1-x)Sb中Mn含量逐渐由近表面处的x = 0.09下降到晶片内部的x = 0。电化学C-V测得单晶的空穴浓度高达1 * 10~(21)cm~(-3)，表明Mn_xGa_(1-x)Sb单晶中大部分Mn原子占据Ga位，起受主作用。

立方相GaN外延层的表面起伏和高密度孪晶与六角相

利用扫描电子显微镜(SEM)、原子力显微镜(AFM)、透射电子显微镜(TEM)和X射线衍射(XRD)技术研究了低压金属有机化学气相淀积(LP-MOCVD)的立方相GaN/GaAs(001)外延层的表面起伏特征，及其与外延层极性和内部六角相、立方相微孪晶之间的联系。结果表明外延表面存在有大量沿[1-10]方向延伸的条带状台阶，而表面起伏处对应着高密度的六角相或立方相微孪晶，在表面平整的区域内其密度则较低。{111}_(Ga)和{111}_N面上形成六角相和微孪晶概率的明显差异是导致外延层表面台阶状起伏特征的根本原因。

自组装InAs/GaAs量子点材料和量子点激光器

利用分子束外延技术和Stranski-Krastanow生长模式，系统研究In(Ga)As/GaAs,InAlAs/AlGaAs/GaAs,In(Ga)As/InAlAs/InP材料体系应变自组装量子点的形成和演化。通过调节实验条件，可以对量子点的空间排列及有序性进行控制，并实现了InP衬底上量子点向量子线的渡越。研制出激射波长λ=960nm，条宽100μm，腔长800μm的InAs/GaAs量子点激光器，室温连续输出功率大于1W，室温阈值电流密度218A/cm~2,0.53W室温连续工作寿命超过3000h。