摘要
ＩｎｘＧａ１－ｘＡｓ缓冲层上生长ＩｎｙＧａ１－ｙＡｓ／ＧａＡｓ超晶格（ｘ＜ｙ）．阱层处于压缩应变，垒层处于伸张应变，其厚度均小于ＭａｔｈｅｗｓＢｌａｋｅｓｌｅｅ（ＭＢ）平衡理论计算的临界厚度．透射电子显微镜及俄歇电子能谱、二级离子质谱测试发现，ＧａＡｓ／ＩｎｙＧａ１－ｙＡｓ界面铟组分过渡区比ＩｎｙＧａ１－ｙＡｓ／ＧａＡｓ界面铟组分过渡区窄；ＩｎｙＧａ１－ｙＡｓ合金阱层中，靠近ＧａＡｓ／ＩｎｙＧａ１－ｙＡｓ界面一端的铟组分更大．用ＩｎｙＧａ１－ｙＡｓ合金层中铟的分凝理论解释了超晶格中铟组分的分布特征．透射电子显微镜观察表明，ＧａＡｓ／ＩｎｙＧａ１－ｙＡｓ界面比ＩｎｙＧａ１－ｙＡｓ／ＧａＡｓ界面平整．提出一种新的弛豫机制来解释压缩应变和伸张应变的不同，对两个界面特性的差异也给予解释．
The In y Ga 1- y As/GaAs superlattice with an In x Ga 1- x As (x<y) buffer layer was grown by metal organic chemical vapor deposition method. The well layer was subjected to a compressive strain and the barrier layer a tensile strain. However, both layers were not thicker than the calculated critical thickness based on the Matthews Blakeslee equilibrium theory. According to the measurements of TEM, SIMS, AES, we found that the composition gradient region at the GaAs/In y Ga 1- y As interface was narrower than that at the In y Ga 1- y As/GaAs interface; in In y Ga 1- y As alloy layer, the composition near the GaAs/In y Ga 1- y As interface was larger than that near the other interface. For the first time, we have explained the composition profile in these kinds of superlattices based on the indium segregation theory. In addition, a new strain relaxation model was presented to explain the differences in the smoothness between the two interfaces.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
1997年第9期1808-1816,共9页
Acta Physica Sinica
