Effect of deposition parameters on SiOx-enhanced intermixing in GaAs/AlGaAs quantum wells

Precise tailoring of the electrical and optical properties of devices is an important issue in the development of optoelectronic integrated circuits. As such, post-growth tailoring techniques of the bandgap such as intermixing/interdiffusion becomes an attractive method as it provides a simple way of integrating devices of different functionality onto a single chip without the need for regrowth. A commonly used technique for achieving intermixing is by impurity-free vacancy diffusion (IFVD) where an encapsulant is deposited on the surface of the sample and then heated to high temperatures to initiate the interdiffusion process. Nevertheless, this technique suffers from the lack of controllability and reproducibility primarily because of various techniques and parameters used for depositing the encapsulant. Thus, for IFVD to be successfully utilized in device fabrication, systematic studies are required to correlate the quality of the encapsulants with intermixing. In this paper, we studied the effect of deposition temperature and flow rates of silane and nitrous oxide on SiO _x-enhanced intermixing in GaAs/AlGaAs quantum wells