화학공학소재연구정보센터
Journal of Vacuum Science & Technology B, Vol.13, No.4, 1760-1765, 1995
Optical Studies of Heterointerfacial Growth Interrupts in Type-II GaAs/AlAs Superlattices by Time-Resolved Photoluminescence Imaging
We have quantitatively characterized the heterointerfaces in type-II GaAs/AlAs short-period structures with various types of growth interrupts. The quality of the heterointerfaces is governed by two factors : the magnitude of the potential fluctuations or interface roughness and the density of nonradiative defect centers incorporated at the heterointerfaces during growth. We have quantified these aspects of the heterointerfaces through photoluminescence (PL), PL time-decay, and time-resolved PL-imaging measurements. We find that growth interrupts at the normal heterointerfaces significantly improves the quality of the interfaces over growth with no interrupts in regard to the interface roughness. Further, the transport of the excitons along the heterointerfaces may be explained by interface roughness induced scattering. We also find that growth interrupts at only the normal interfaces substantially reduces the nonradiative trap densities at the heterointerfaces.