Improvements of Cell Properties by Thermal Cycle Annealing in Lattice-mismatched InGaAs

摘要

Lattice-mismatched In_(0.16)Ga_(0.84)As solar cells were grown on GaAs substrates using graded In_xGa_(1-x)As and homogenous In_(0.16)Ga_(0.84)As buffer layers. The indium composition x of the graded buffer was changed from 0 to 16% continuously. Thermal cycle annealing (TCA) was applied after the growth of graded buffer layers. The impact of TCA on the solar cell properties and the spectral response was investigated. The minority carrier lifetime in p-type In_(0.16)Ga_(0.84)As layers improved after TCA treatment, despite the TCA step being performed after the growth of the graded buffer. Electron beam induced current measurements and deep level transient Fourier spectroscopy showed a reduction of the defect density in the p-type In_(0.16)Ga_(0.84)As layer due to TCA.