We report an approach to improve the uniformity of self-assembledInAsquantumdots (QDs) grown on a strained In0.12Ga0.88As buffer layer on GaAs substrates by low-pressuremetalorganicchemicalvapordeposition. By inserting a thin GaAs layer between the InAs QD layer and the In0.12Ga0.88As buffer layer and examining its thickness effect, we demonstrate that the photoluminescence (PL) inhomogeneous
Fabrication of abruptInGaP∕GaAsheterointerfaces has been difficult using metalorganicvaporphaseepitaxy (MOVPE) due to the exchange of P and As during the fabrication steps. An optimizedgas-switchingsequence to fabricate heterointerface of InGaP on GaAs layer by MOVPE was previously developed in which the unstable top surface layer of GaAs is stabilized and the exchange of P and As between InGaP and GaAs
由于在制造步骤中 P 和 As 的交换,使用金属有机气相外延 (MOVPE) 制造突然的 InGaP∕GaAs 异质界面一直很困难。先前开发了通过 MOVPE 在 GaAs 层上制造 InGaP 异质界面的优化气体开关序列,其中稳定了不稳定的 GaAs 顶面层,并抑制了 InGaP 和 GaAs 层之间的 P 和 As 交换。在这项研究中,通过使用扫描透射电子显微镜 (STEM) 定量评估了这种优化的气体切换序列的效果。通过在 STEM 中使用 Z 对比方法揭示了原子层级界面处从 GaAs 到 InGaP 的原子组成变化。
Effects of AlAs interfacial layer on material and optical properties of GaAs∕Ge(100) epitaxy
作者:C. K. Chia、J. R. Dong、D. Z. Chi、A. Sridhara、A. S. W. Wong、M. Suryana、G. K. Dalapati、S. J. Chua、S. J. Lee
DOI:10.1063/1.2908042
日期:2008.4.7
GaAs∕AlAs∕Ge(100) samples grown at 650°C with AlAsinterfaciallayer thickness of 0, 10, 20, and 30nm were characterized using transmission electron microscopy, secondary ion mass spectrometry (SIMS), and photoluminescence (PL) techniques. SIMS results indicate that the presence of an ultrathin AlAsinterfaciallayer at the GaAs∕Ge interface has dramatically blocked the cross diffusion of Ge, Ga, and
GaAs∕AlAs∕Ge(100) 样品在 650°C 下生长,AlAs 界面层厚度为 0、10、20 和 30nm,使用透射电子显微镜、二次离子质谱 (SIMS) 和光致发光 (PL) 技术进行表征。SIMS 结果表明,在 GaAs∕Ge 界面存在超薄的 AlAs 界面层极大地阻止了 Ge、Ga 和 As 原子的交叉扩散,这归因于较高的 Al-As 键能。发现具有薄 AlAs 界面层的 GaAs 外延的光学质量随着源自 Ge 基复合物的 PL 的完全消除而得到改善,这与 SIMS 结果证实。
High-nitrogen-content InGaAsN films on GaAs grown by metalorganic vapor phase epitaxy with TBAs and DMHy
94 As 0.979 N 0.021 /GaAsfilm corresponding to the room-temperature E 0 transition energy of 1.11 eV was achieved. It is noticeable that the structural and optical properties of the InGaAsNfilmsgrown using TBAs strongly depends on the N content, as in the case of corresponding filmsgrown using AsH 3 . Besides, the PR spectral feature demonstrated the growth of the InGaAsNfilm whose bandgap is lower
我们研究了在 GaAs 上生长高 N 含量 In x Ga 1-x As 1-y N y 薄膜的 MOVPE 生长参数及其结构和光学特性。发现 N 掺入控制主要取决于 1,1-二甲基肼 (DMHy) 摩尔流速和生长温度。随着 DMHy 摩尔流速的增加,高分辨率 X 射线衍射测量显示出明显的衍射峰位移,代表 N 掺入量的增加。另一方面,随着生长温度从 650 °C 降低到 500 °C,N 含量从 y ∼ 0.5% 增加到 3.6%。可以清楚地观察到随着 N 含量的增加,光致发光 (PL) 峰和光反射 (PR) 信号 (E 0 跃迁) 的红移。最后,晶格匹配的 In 0.06 Ga 0.94 As 0.979 N 0。实现了对应于1.11eV的室温E 0 跃迁能量的021 /GaAs膜。值得注意的是,使用 TBA 生长的 InGaAsN 薄膜的结构和光学特性在很大程度上取决于 N 含量,正如使用
MOVPE growth and optical characterization of GaAsN films with higher nitrogen concentrations
transition could be detected and the bandgap energy was redshifted to 1.16 eV in 1.9%-N GaAsNfilm. But, in higher N-content films no peak could be detected. So, post growth annealing in the reactor was applied to 4.7% and 5.1%-N films, and resulted in an enhancement of the PL peak intensity, and the bandgap energy of 5.1%-N film was consequently determined to be 0.95 eV at room temperature.
我们使用叔丁基胂 (TBA) 作为 As 前体,通过金属有机气相外延 (MOVPE) 在 GaAs(001) 衬底上成功地生长了高达 5.1% 的高 N 含量 GaAsN 薄膜。窄的 X 射线衍射 (XRD) 峰和清晰的 Pendellosung 条纹表明 GaAsN/GaAs 界面相当平坦,GaAsN 层是均匀的。通过在 10 K 的光致发光 (PL) 测量,可以检测到与近带边缘跃迁相关的清晰 PL 峰,并且在 1.9%-N GaAsN 薄膜中带隙能量红移至 1.16 eV。但是,在 N 含量较高的薄膜中,无法检测到峰值。因此,反应器中的后生长退火应用于 4.7% 和 5.1%-N 薄膜,导致 PL 峰强度增强,因此确定 5.1%-N 薄膜的带隙能量在室温下为 0.95 eV温度。