Zn/P ratio and microstructure defines carrier density and electrical transport mechanism in earth-abundant Zn3-xP2+y thin films

First-principles study of intrinsic and hydrogen point defects in the earth-abundant photovoltaic absorber Zn3P2

“…This implies that good photovoltaic performance is not guaranteed for nonstoichiometric P-rich Zn 3 P 2 samples which have become the focus of recent experimental studies. 17,24,25 This analysis would however require a systematic study of the nonradiative carrier capture coefficients (cross sections) which could vary considerably between different deep levels, 55–59 which is beyond the scope of the present work.…”

“…23 In order to clarify these conicting results, recently Stutz et al and Paul et al studied the effect of compositional stoichiometry variations on the structural, electrical, and optical properties of monocrystalline Zn 3 P 2 thin lms, yet a conclusive identication of the source for the p-type conductivity, whether it is due to P i or V Zn , has remained elusive. 24,25 On the other hand, less attention has been devoted to identifying deep-level defects in Zn 3 P 2 , in spite of accumulating experimental evidence for presence of deep levels in the band gap of Zn 3 P 2 . [26][27][28] Deep-level defects may act as nonradiative carrier recombination centers which would limit the efficiency of Zn 3 P 2 solar cells.…”