摘要
用分子束外延生长了不同组分ｘ的Ｚｎ１－ｘＭｎｘＳｅ外延膜和Ｚｎ１－ｘＭｎｘＳｅ／ＺｎＳｅ超晶格．由于Ｚｎ１－ｘＭｎｘＳｅ的能隙Ｅｇ随组分变化在低组分区形成弓形，且弓形的范围随温度变化的反常特性，首次在光致发光谱（ＰＬ）中观测到当温度升高时，Ｚｎ１－ｘＭｎｘＳｅ／Ｚｎｓｅ超晶格中由ＺｎＳｅ为阱、Ｚｎ１－ｘＳｅ为垒转换成Ｚｎ１－ｘＳｅ为阱，ＺｎＳｅ为垒．瞬态光致发光结果表明，Ｚｎ１－ｘＭｎｘＳｅ／ＺｎＳｅ超晶格中Ｍｎ＋＋离子的激发态弛豫时间远大于Ｚｎ１＝ｘＭｎｘＳｅ外延模中Ｍｎ＋＋离子的弛豫时间，这可能是由于超晶格中界面效应引起Ｍｎ＋＋离子间交换相互作用改变所致．
Abstract Zn1-xMnxSe films and Zn1-xMnxSe/ZnSe superlattices with different composition x have been grown by molecular beam epitaxy(MBE).Superlattice structure withsmall values of x transfered from ZnSe as well to Zn1-xMnxSe as well has been observedfor the first time by PL measurements when the temperature increases.It is due to theanomalous behavior of energy gap at low x in Zn1-xMnxSe,which forms a bowing regionand the shape of this bowing and the dip in energy are dependent strongly as the temperature varies.It has been found by time-resolved photoluminescence spectra that the relaxation time of Mn++ ions excited states is much longer in superlattices than in films.This may be contributed to lowdimensional scaling effect on the exchange interaction between Mn++ ions.
基金
国家自然科学基金
关键词
稀磁半导体
ZnMnSe薄膜
外延生长
超晶格
Magnetic properties
Molecular beam epitaxy
Optical properties
Semiconducting manganese compounds
Semiconducting selenium compounds
Superlattices
