ZnMgSSe／GaAs薄膜的分子束外延生长及其特性研究

Molecular Beam Epitaxial Growth and Characterization of ZnMgSSe on GaAs

我们用分子束外延法在ＧａＡｓ（１００）衬底上生长一种新型的Ⅱ－Ⅳ族宽禁带化合物薄膜Ｚｎ１－ｘＭｇｘＳｙＳｅ１－ｙ．改变生长条件，可以控制Ｍｇ和Ｓ的组分在０≤ｘ≤１，０≤ｙ≤１．Ｍｇ和Ｓ的组分用俄歇电子能谱测定．用Ｘ－射线衍射技术对样品结构进行的研究发现，对任意Ｍｇ和Ｓ的组分，ＺｎＭｇＳＳｅ均为闪锌矿结构．用椭圆偏振光谱仪对材料的能隙和折射率进行的研究表明，加入Ｍｇ以后ＺｎＭｇＳＳｅ样品的折射率比ＺｎＳＳｅ样品的折射率要小，并且ＺｎＭｇＳＳｅ样品的折射率随民的增大而变小．合理选择ｘ、ｙ，在２．８ｅＶ＜Ｅｇ＜３．６ｅＶ均能得到与ＧａＡｓ晶格匹配的Ｚｎ１－ｘＭｇｘＳｙＳｅ１－ｙ．

Abstract A new kind of Ⅱ-Ⅳ wide band-gap Zn1-xMgxSySe1-y films was grown on GaAs (100) substrates by molecular beam epitaxy. Changing the growth conditions, we can grow films with 0≤x≤1, 0≤y≤1. The Mg and S compositions of the films were measured by Auger electron spectroscopy. The structural characteristics of the films were studied by X-ray diffraction, and the experimental results have shown that the films are zinc-blende structure at any Mg and S contents. The band-gap energies and the refractive indices of ZnMgSSe alloys were studied by ellipsometry method at room temperature. We have found that the refractive index n of Zn1-xMgxSySe1-y decreases as Eg increases. The experimental results have also shown that band-gap energy can be varied from 2. 8 to 3.6eV, maintaining lattice-matching to a GaAs (100) substrate at proper proportion of Mg and S compositions.