Highly efficient and ultra-fast visible-blind ultra-violet detectors

A two-step molecular beam epitaxy growth approach, which enjoys the advantage of being wet-chemical-etching free, was developed to fabricate a ZnSTe-based Schottky barrier photovoltaic ultra-violet (UV) detector array on GaP (100). Visible blind and UV sensitive response were achieved with peak UV responsivity of 1.23 A/W and 1.2×10⁶ V/W at 320 nm. Through the measurement of the photovoltage output as a function of incident photon power, the built-in potential of the detector was determined to be 1.7 V. Temporal response measurement of the device shows that the photocurrent decays with a time constant as fast as 1.2 ns, limited apparently by the RC time constant of the detector structure