Miniband structures in semiconductor superlattices investigated by modulated-reflectance spectroscopy

通过调制反射光谱研究半导体超晶格中的微带结构

• 批准号: 07640450
• 负责人: NAKAYAMA Masaaki
• 金额: $ 1.41万
• 依托单位: Osaka City University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07640450/
• 关键词: superlattice; miniband; III-V chemical compound semiconductor; photoreflectance; electroreflectance; Franz-Keldysh oscillation; effective-mass approximation; Wannier-Stark localization

1. Miniband structure of (GaAs)_<10>/(AIAs)_m superlattices (SLs) with m=1,2,4, and 6 monolayrs (1 monolayr=-0.28nm) have been systematically investigated by using photoreflectance (PR) spectroscopy. The optical transitions at the GAMMA and pi (miniband edge) critical points were celarly observed in the SL with one-monolayr AlAs. Furthermore, Franz-Keldysh (FK) ascillations at the miniband critical points were successfully detected. From the analysis of the FK oscillation profiles, it has been found that the miniband mass at GAMMA point is almost equal to the mass of bulk GaAs and that the pi-point mass is bout one third of the GAMMA-point mass.2.In (GaAs)_<10>/(Al_<0.3>Ga_<0.7>As)_<10>SL and (InAs)_1/(GaAs)_mSLs with m=10 and 30 monolayrs, the optical transitions associated with the below-barrier and above-barrier minibands were clearly obwerved by using PR spectroscopy.In a (GaAs)_<25>/(Al_<0.1>Ga_<0.9>As)_<12>SL embedded in a p-i-n diode, the electric-field dependence of the optical transitions were observed by using electroreflectance (ER) spectroscopy. It has been found that the change of the FK-oscillation profiles with increasing the electric field reflects the transformation process from the minibands to the Wannier-Stark (WS) localization states. Furthermore, it has been confirmed that the electric field transforms the above-barrier minibands into the WS-localization states.The above experimental results are consistently explained by the miniband structures calculated by using an effective-mass approximation.

1。（GAAS）_ <10>/（AIAS）_M超级晶格（SLS）的迷你班结构，具有M = 1,2,4，而6个Monolayrs（1个Monolayr = -0.28nm）已使用PRORETRECTANCE进行了系统地研究（PR（PR） ）光谱学。在具有一个单子las的SL中观察到伽马和PI（小型边缘）临界点处的光学转变。此外，成功检测到了Miniband关键点处的Franz-Keldysh（FK）刺激性。从对FK振荡曲线的分析中，已经发现，伽马点的小型质量几乎等于散装GAA的质量，并且PI点质量是伽马点质量的三分之一。 （gaas）_ <10>/（al_ <0.3> ga__ <0.7> as）_ <10> sl和（inas）_1/（gaAs）_msls，具有m = 10和30 monolayrs，与以下 - 通过使用PR光谱法明确地遵守了障碍物和屏障小型班通过使用电触觉（ER）光谱观察光学转变的依赖性。已经发现，随着电场的增加，FK振荡轮廓的变化反映了从迷你班到Wannier-Stark（WS）定位状态的转换过程。此外，已经证实，电场将上层式的小型机转换为WS-localization态。上述实验结果一致地通过使用有效的质量近似值计算得出的小型结构来解释。

项目成果

M. Nakayama: "Miniband structures and effective masses in GaAs/AlAs superlattices with ultra-thin AlAs barriers" Solid State Communications. (to be published). (1997)

M. Nakayama：“具有超薄 AlAs 势垒的 GaAs/AlAs 超晶格中的微带结构和有效质量”固态通信。

M.Ando: "Franz-Keldysh oscillations at the miniband edge in a GaAs/Al_XGa_<1-X>As superlatice" Superlatices and Microstructures. (to be published). (1997)

M.Ando：“GaAs/Al_XGa_<1-X>As 超晶格中微带边缘的 Franz-Keldysh 振荡”超晶格和微观结构。

M.Nakayama: "Stark-Ladder Formation of Above-Barrier Minibands in a GaAs/Al_xGa_<1-x>As Superlattice" Proceedings of 14th Electronic Materials Symposiun(Izu-Nagaoka,July,1995). 67-68 (1995)

M.Nakayama：“GaAs/Al_xGa_<1-x>As 超晶格中势垒上方微带的 Stark-Ladder Formation”第 14 届电子材料研讨会论文集（Izu-Nagaoka，1995 年 7 月）。

M. Ando: "Franz-Keldysh oscillations at the miniband edge in a GaAs/Al_xGa_<1-x>As superlattice" Superlattices and Microstructures. (to be published). (1997)

M. Ando：“GaAs/Al_xGa_<1-x>As 超晶格中微带边缘的 Franz-Keldysh 振荡”超晶格和微结构。

M.Nakayama: "Stark-ladder formation of above-barrier minibands in a GaAs/Al_XGa_<1-X>As superlatice" Records of 14th Electronic Materials Symposium (Izu-Nagaoka, July, 1995). 67-68 (1995)

M.Nakayama：“GaAs/Al_XGa_<1-X>As超晶格中势垒上方微带的Stark-ladder形成”第14届电子材料研讨会记录（Izu-Nagaoka，1995年7月）。