Reverse bias breakdown and photocurrent gain in CH3NH3PbBr3 films

Perovskite films are promising candidates for fast, sensitive, and large area photodetectors. A gain in perovskite based detectors has been observed in several architectures, but a model describing the underlying mechanism is still missing or at least incomplete. Here, we present measurements of CH3NH3PbBr3 films under reverse bias exhibiting breakdown at 4–5 V and small photocurrent gain ≲ 2, which based on a phenomenological model, we explain tentatively by tunnel-assisted injection from the TiO2 electron transport layer and carrier multiplication, mediated by the electric field due to mobile ions.