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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

为了向半导体注入自旋极化电流，我们采用分子束外延（MBE）技术制备了铁磁/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。主要研究成果如下：利用分子束外延技术成功地在铁磁半导体（Ga，Mn）As/GaAs半导体（In，Ga）As pn结发光二极管中实现了向GaAs半导体的电自旋注入。我们在铁磁结的电致发光光谱中观察到了滞后极化现象。在晶格弛豫的n-In_xGa_As（<1-x> ...更多信息 x = 0.15 - 0.18）缓冲层，使得（Ga，Mn）As的易磁化轴垂直于平面。为了研究（Ga，Mn）As/GaAs异质界面的价带排列，我们制备了（Ga，Mn）As/i-GaAs/p-GaAs p-i-p结构，并测量了它们的电流-电压特性随温度的变化。结果表明，这种p-i-p结构的电流-电压特性依赖于偏置电压的极性，表明空穴电流从（Ga，Mn）As注入GaAs时，在界面处存在势垒.假设电流主要由肖特基势垒上的热发射决定，我们分析了结果，发现从（Ga，Mn）As的费米能测量的势垒高度约为100 meV，这与（Ga，Mn）As中的Mn浓度无关。少