GaN/GaAs(001)与GaN/Al_2O_3(0001)外延层光辅助湿法腐蚀行为的比较

研究了用金属有机物气相外延（MOVPE）方法在GaAs(001)衬底上生长的立方相GaN(c-GaN)外延层的光辅助湿法腐蚀特性，并和生长在蓝宝石（0001）衬底上的六方相GaN(h-GaN)外延层的光辅助湿法座蚀特性进行了比较。实验发现c-GaN膜的暗态电流和光电流的变化不同于h-GaN膜的腐蚀电流的变化规律。对引起上述差异的原因进行了简单的讨论。

Etching Behavior of GaN/GaAs(001) Epilayers Grown by MOVPE

Wet etching characteristics of cubic GAN (c-GaN) thin films grown on GaAs(001) by metalorganic vapor phase epitaxy (MOVPE) are investigated. The samples are etched in HCl, H_3PO_4, KOH aqueous solutions, and molten KOH at temperatures in the range of 90～300 ℃. It is found that different solution produces different etch figure on the surfaces of a sample. KOH-based solutions produce rectangular pits rather than square pits. The etch pits elongate in [1(1-bar)0] direction, indicating asymmetric etching behavior in the two orthogonal <110> directions. An explanation based on relative reactivity of the various crystallographic planes is employed to interpret qualitatively the asymmetric etching behavior. In addition, it is found that KOH aqueous solution would be more suitable than molten KOH and the two acids for the evaluation of stacking faults in c-GaN epilayers.

立方相GaN/GaAs（001）外延层中六角相的分布特征

于2010-11-23批量导入

Si（001）衬底上APCVD生长3C-SiC薄膜的微孪晶及含量

于2010-11-23批量导入

Si（001）衬底上方形3C-SiC岛的LPCVD生长

于2010-11-23批量导入

GaAs（001）衬底上MOCVD生长的立方相GaN外延薄膜的光学性质研究

于2010-11-23批量导入

MOCVD方法制备的立方GaN/GaAs（001）中六角相含量退火行为的研究

采用高温热退火的方法，在不同条件下对低压MOCVD在GaAs(001)衬底制备的立方GaN薄膜进行处理，利用光致发光光谱和Raman散射光谱来研究六角相的含量变化。报道了亚稳态立方GaN的六角相含量变化条件及其光学特征。在GaN/GaAs之间存在一个界面层，高温退火时，来自界面层的TO_B，LO_B声子的强度降低，而来自六角相的E_2声子增强，说明六角相含量增加。样品原结晶质量欠佳是六角相含量变化发生的主要原因。在较低的温度下，六角相含量没有明显变化，而且与退火时间无关。

Al_2O_3/Si(001)衬底上GaN外延薄膜的制备

于2010-11-23批量导入

MBE GaAs/GaP（001）异质外延层结构参数的X射线双晶衍射研究

于2010-11-23批量导入

MBE[（GaAs）l（Ga（1-x）AlxAs）m]n/GaAs（001）一维超晶格的X射线双晶...

于2010-11-23批量导入

Optical characterization of the Ge/Si (001) islands in multilayer structure

We show that the observed temperature dependence of the photoluminescence (PL) features can be consistently explained in terms of thermally activated carrier transfer processes in a multilayer structure of the self-organized Ge/Si(001) islands. The type II (electron confinement in Si) behavior of the Ge/Si islands is verified. With elevated temperature, the thermally activated electrons and holes enter the Ge islands from the Si and from the wetting layer (WL), respectively. An involvement of the type I (spatially direct) into type II (spatially indirect) recombination transition takes place at a high temperature.

The growth and characterization of GaN grown on a gamma-Al2O3/(001) Si substrate by metalorganic vapor phase epitaxy

Wurtzite single crystal GaN films have been grown onto a gamma-Al2O3/Si(001) substrate in a horizontal-type low pressure MOVPE system. A thin gamma-Al2O3 layer is an intermediate layer for the growth of single crystal GaN on Si although it is only an oriented polycrystal film as shown by reflection high electron diffraction. Moreover, the oxide is not yet converted to a fully single crystal film, even at the stage of high temperature for the GaN layer as studied by transmission electron microscopy. Double crystal x-ray linewidth of (0002) peak of the 1.3 mu m sample is 54 arcmin and the films have heavy mosaic structures. A near band edge peaking at 3.4 eV at room temperature is observed by photoluminescence spectroscopy. Raman scattering does not detect any cubic phase coexistence.

The effect of low temperature GaAs nucleation on the growth of GaN on Silicon (001) during MOVPE process

High quality cubic GaN was grown on Silicon (001) by metalorganic vapor phase epitaxy (MOVPE) using a GaAs nucleation layer grown at low temperature. The influence of various nucleation conditions on the GaN epilayers' quality was investigated. We found that the GaAs nucleation layer grown by atomic layer epitaxy (ALE) could improve the quality of GaN films by depressing the formation of mixed phase. Photoluminescence (PL) and X-ray diffraction were used to characterize the properties of GaN epilayers. High quality GaN epilayers with PL full width at half maximum (FWHM) of 130meV at room temperature and X-ray FWHM of 70 arc-min were obtained by using 10-20nm GaAs nucleation layer grown by ALE.