摘要
用深能级瞬态谱（ＤＬＴＳ）研究了分子束外延生长的Ｇｅ０．４Ｓｉ０．６／Ｓｉ多量子阱与Ｇｅ／Ｓｉ应变超晶格样品中深能级中心的性质．在两种样品中都观测到两个多数载流子中心和一个少数载流子中心．在Ｇｅ０．４Ｓｉ０．６／Ｓｉ多量子阱样品中深中心Ｅ２ 的能级位置为ＥＣ－ ０．３０ｅＶ，Ｅ３ 的能级位置为ＥＣ－ ０．２２ｅＶ．并且在正向注入下随着Ｅ２ 峰的消失观测到一个少数载流子峰ＳＨ１，其能级位置为ＥＶ＋ ０．６８ｅＶ．在Ｇｅ／Ｓｉ应变超晶格中，深中心Ｈ１ 的能级位置为ＥＶ＋ ０．４４ｅＶ，深中心Ｈ２的能级位置为ＥＶ＋ ０．２４ｅＶ．发现反向多数载流子注入脉冲下随着多子峰Ｈ１ 的消失观测到了少子峰ＳＥ１，少子峰能级位置为ＥＣ－ ０．７５ｅＶ．Ｅ２ 和ＳＨ１、Ｈ１ 和ＳＥ１ 两个峰可能分别由同一缺陷引起，该缺陷是与位错有关的深中心．
The Properties of deep centers in Ge 0.4 Si 0.6 /Si multiple quantum well and Ge/Si strained superlattice grown by MBE are investigated using Deep Level Transient Spectroscopy (DLTS). In both samples,two deep majority carrier centers and one minority carrier center are observed.For the sample of Ge 0.4 Si 0.6 /Si multiple quantum well,E2 peak locates at E\- C-0.30eV,E3 peak locates at E \-C-0.22eV. Under minority\|carriers filling pulse conditions,SH1 peak is observed with the E2 peak disappears.It locates at E V+0.68eV. For the sample of Ge/Si strained superlattice,the high temperature peak H1 locates at E V+0.44eV,low temperature peak H2 locates at E V+0.24eV. Under majority\|carriers filling pulse conditions,anomalous minority\|carrier electron trapping SE1 are also observed. It locates at E C-0.75eV. We think that the E2 and SH1,H1 and SE1 may be caused by the same defect respectively. The defect may be a recombination center related to dislocation. It is very meaningful to make clear the causes of the two common defects in the samples of Ge 0.4 Si 0.6 /Si multiple quantum well and Ge/Si stranined superlattice.
