High-Gain Ultraviolet Avalanche Photodiodes Using a ZnSe-Based Organic–Inorganic Hybrid Structure

We have developed high-gain and highly sensitive ZnSe-based organic–inorganic hybrid ultraviolet avalanche photodiodes (UV-APDs). The inorganic ZnSe-based wafers (i-ZnSSe active layer/n-ZnSSe) were grown by molecular beam epitaxy (MBE) on n -type GaAs substrates. The inorganic UV-transparent conducting polymer window layers of poly 3,4-ethylenedioxythiophene:poly-styrenesulfonate (PEDOT:PSS) were formed by spin-coating and a photolithography technique instead of the inkjet printing technique, which we previously reported. We have obtained a thin uniform window layer with a mesa-shaped edge by an optimized photolithography process. The leakage current before the breakdown voltage was suppressed to