Theoretical analysis of non-radiative multiphonon recombination activity of intrinsic defects in CdTe

We present an analysis of recombination activity of intrinsic defects (V-Cd, Te-Cd, V-Te, and Te-i) in CdTe based on the multiphonon single-mode carrier-capture model, with vibronic parameters obtained using hybrid density functional theory. This analysis allows us to determine the defects and the corresponding electronic processes that have high trapping rates for electrons, for holes, or for both. The latter, being potentially the most active recombination centers, decreases the carrier lifetime in the absorber layer of a CdTe solar cell. Taking into account the relatively high calculated capture cross-sections of the Te-Cd antisite defect (sigma = 8.7 x 10(-15) cm(2) for electron capture on Te-Cd(+2) defect, sigma = 6.8 x 10(-14) cm(2) for hole capture on Te-Cd(+1) defect at room temperature) and its deep trapping level (0.41 eV for +2/+1 level), we conclude that this defect is the most active recombination center among the intrinsic defects in p-type CdTe. Other processes that do not lead to effective recombination are: (i) fast hole capture on Te-i(+1) defect (sigma = 1.1 x 10(-13) cm(-2)), (ii) electron capture on Te-Cd(+1) defect (sigma = 2.9 x 10(-15) cm(-2)), (iii) somewhat slower hole capture on Te-Cd(0) defect (sigma = 9.4 x 10(-20) cm(-2)), (iv) hole capture on V-Cd(-1) defect (sigma = 7 x 10(-19) cm(2)), and (v) electron capture on Te-i(+1) defect (sigma = 4.4 x 10(-19) cm(-2)). The cross-sections are found to be negligibly small for the remaining capture processes. VC 2016 AIP Publishing LLC.