At present, the experimental techniques of deep level detection in semiconductors can be roughly divided into three categories, namely junction capacitance technique, spectroscopy technique and electron paramagnetic resonance technique.
Based on the advantages of strained quantum well and its application status and prospects, the optical properties of InGaAs / GaAs Strained Quantum Well materials are taken as the main research direction. On the basis of discussing the energy level characteristics of strained quantum well, the factors influencing the luminescence quality of strained quantum well are analyzed comprehensively; For InGaAs / GaAs Strained Quantum Well materials grown by molecular beam epitaxy (MBE) in our laboratory, the temperature dependent PL spectra were measured, The effects of strain compensation and growth pause on the luminescence properties of InGaAs / GaAs Strained Quantum Wells are studied and discussed respectively.
The main research contents and achievements of spetrum for gaas solar cell include the following aspects:
1. The exciton transition energy of InGaAs thin layer considering strained heterojunction and stress is studied theoretically.
2. Starting from the structure of strained quantum wells, the effects of strain compensation on hot carrier effect and scattering in InGaAs / GaAs quantum wells are analyzed, and how to improve the luminescent quality of materials through these effects. The introduction of strain compensation changes the temperature coefficient of varshni, which affects the red shift rate of luminescent peak with the increase of temperature, The varshni temperature coefficients of a and B are obtained α= three point five four eight × 10-4eV/K, β A=100.0K: α B=3.845x10-4eV/K, β
Based on the growth mode of strained quantum well, the effect of interface pause on the surface segregation of in atom and the disorder of ternary compound alloy during the growth of well layer were analyzed. The PL spectra of two groups of samples with and without in atom pause were measured. The same interface pause was adopted in both samples, The effect of in atom pause on the PL spectra of InGaAs / GaAs quantum wells is analyzed, and the effect of in atom pause on the in atom localization is discussed. Theoretically, the introduction of appropriate in atom pause in the well layer growth process can make the GA and in atoms of the same family diffuse better, thus making the composition of InGaAs quantum wells more uniform.