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． We developed a novel type II-IV broad bandgap thin film Zn1-xMgxSySe1-y on GaAs (100) substrate by molecular beam epitaxy. Change the growth conditions, you can control the composition of Mg and S in the 0 ≤ x ≤ 1, 0 ≤ y ≤ 1. The components of Mg and S were determined by Auger electron spectroscopy. A study of the sample structure by X-ray diffraction revealed that ZnMgSSe is a sphalerite structure for any of the Mg and S components. The research on the energy gap and refractive index of the material by ellipsometer shows that the refractive index of ZnMgSSe sample after adding Mg is smaller than that of ZnSSe sample, and the refractive index of ZnMgSSe sample decreases with the increasing of the population. Reasonable choice of x, y, at 2.8eV