Growth Dynamics and Properties of Compound Semiconductor Layers Prepared by Low Temperature Molecular Beam Epitaxy

低温分子束外延制备化合物半导体层的生长动力学和性能

基本信息

批准号：
11650002
负责人：
OHNO Yuzo
金额：
$ 2.3万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

In order to inject spin-polarized electrical current into semiconductors, we fabricated ferromagnetic/nonmagnetic semiconductor heterostructures by employing MBE regrowth technique, and investigated their current-voltage characteristics and electroluminescence polarization. The summary of the research results is as follows :Electrical spin injection into nonmagnetic semiconductor is successfully achieved in ferromagnetic semiconductor (Ga, Mn) As/nonmagnetic semiconductor (In, Ga) As pn junction light emitting diodes prepared by molecular beam epitaxy. We observed hysteretic polarization in electroluminescence spectra of ferromagnetic/nonmagnetic pn junction. The degree of the remanent electroluminescence polarization was about ±1%, of which the temperature dependence is almost proportional to that of the magnetization of (Ga, Mn) As.We fabricated ferromagnetic (Ga, Mn) As/nonmagnetic (In, Ga) As semiconductor light emitting diodes, which are grown on lattice-relaxed n-In_xGa_<1-x>As ( … More x=0.15-0.18) buffer layer so that the magnetic easy axis of (Ga, Mn) As directs perpendicular to the plane. We measured the degree of the polarization of light emitted from the backside of the substrate, and observed hysteretic polarization.In order to clarify the valence band alignment at (Ga, Mn) As/GaAs heterointerface, we fabricated (Ga, Mn) As/i-GaAs/p-GaAs p-i-p structures with different Mn concentration in (Ga, Mu) As, and measured the temperature dependence of current-voltage characteristics of them. It is found that the current-voltage characteristics of such p-i-p structures depend on the polarity of bias voltage, which suggest the existence of a potential barrier at the interface when hole current is injected from (Ga, Mn) As into GaAs. Assuming that the current is dominated by thermal emission over a Schottky barrier, we analyzed the results and found that the barrier height measured from the Fermi energy of (Ga, Mn) As is about 100 meV, which does not depend on the Mn concentration in (Ga, Mn) As. Less

为了向半导体中注入自旋极化电流，我们利用MBE再生技术制备了铁磁/非磁半导体异质结构，并研究了它们的电流-电压特性和电致发光极化特性。研究结果总结如下：电自旋注入非磁。成功实现铁磁半导体（Ga、Mn）As/非磁半导体（In、Ga）As pn结发光我们在铁磁/非磁p-n结的电致发光光谱中观察到了磁滞极化，剩余电致发光极化程度约为±1%，其中温度依赖性几乎与(Ga的磁化强度)成正比。，Mn）As。我们制作了铁磁（Ga，Mn）As/非磁（In，Ga）As半导体发光二极管，生长在晶格弛豫的 n-In_xGa_<1-x>As (… 更多 x=0.15-0.18) 缓冲层上，以便 (Ga, Mn) As 的易磁轴垂直于我们测量的平面。从衬底背面发射的光的偏振程度，并观察到滞后偏振。为了澄清（Ga，Mn）处的价带排列As/GaAs异质界面，我们制作了(Ga, Mu) As中不同Mn浓度的(Ga, Mn) As/i-GaAs/p-GaAs p-i-p结构，并测量了它们的电流-电压特性的温度依赖性。发现这种 p-i-p 结构的电流-电压特性取决于偏置电压的极性，这表明当空穴电流从 (Ga, Mn) As 注入到界面时，界面处存在势垒假设电流以肖特基势垒上的热发射为主，我们分析了结果，发现从 (Ga, Mn) As 的费米能测得的势垒高度约为 100 meV，这与 Mn 无关。 (Ga, Mn) As 浓度较低。