Generation and recombination rates at ZnTe:O intermediate band states

Carrier generation and recombination processes of ZnTeO thin films are studied by time-resolved photoluminescence, where carrier lifetimes at oxygen states and the conduction band are inferred to be >1 μs and <100 ps, respectively. The radiative recombination coefficient for optical transitions from oxygen states to the valence band is extracted to be 1.2×10−10 cm3 sec−1 based on the excitation dependence of decay time constants. Rate equation analysis further suggests an increase in electron lifetime at the conduction band as oxygen states occupation is critical in achieving high conversion efficiency for solar cells based on multiphoton processes in these materials.