电子束蒸发方法研究Mg2Si的薄膜及其光学带隙

摘要

As an advanced ecological friendly semiconducting material,the researches on the preparation methods and optical properties of Mg2Si film play a fundamental role in the applications and development of Mg2 Si films.Semiconducting Mg2 Si films were prepared by electron beam evaporation deposition of Mg film onto Si (111) substrate and subsequent heat treatment under Ar gas atmosphere.X-ray diffraction (XRD),scanning electron microscopy (SEM) and spectrometer were used to characterize and analyze the obtained Mg2Si films.Effects of heat treatment time (3 ～7 h) at 500 ℃ under Ar gas pressure (200 Pa) on the formation of Mg2Si films were investigated.The XRD and SEM results show that semiconducting Mg2Si films are obtained by electron beam evaporation deposition and subsequent heat treatment at 500 ℃ for 3-7 h.4 h is optimal heat treatment time to prepare Mg2 Si films when heat treated at 500 ℃,and the compact Mg2Si films are obtained.The calculational results of infrared transmittance spectra of the Mg2Si films show that the indirect optical bandgap of the Mg2Si films is 0.943 3 eV,and the direct optical bandgap is 1.158 eV.These experimental data are beneficial to the device research and development of the Mg2 Si films in the preparation process and optical properties.%Mg2Si材料作为一种新型环境友好半导体材料,其薄膜制备方法及其光学性质的研究对其应用研发起到基础性作用.采用电子束蒸发方法在Si(111)衬底上沉积Mg膜,在氩气环境下进行热处理以制备Mg2Si半导体薄膜.采用X射线衍射仪(XRD)、扫描电镜(SEM)、分光光度计对制备的Mg2Si薄膜进行表征.在氩气环境、温度500℃、压强200 Pa下,研究热处理时间(时间3-7 h)对Mg2Si薄膜形成的影响.XRD和SEM结果表明:通过电子束蒸发沉积方法在500℃、热处理时间为3～7h能够得到Mg2Si薄膜.热处理温度是500时,最佳热处理时间是4h,得到致密度好的薄膜.通过对薄膜的红外透射谱测试,得到了Mg2Si薄膜的光学带隙,其间接光学带隙值为0.9433 eV,直接光学带隙值为1.1580 eV.实验数据为Mg2Si薄膜的研发在制各工艺和光学性质方面提供参考.