Blue-Violet Avalanche-Photodiode (APD) and its Ionization Coefficients in II-VI Wide Bandgap Compound Grown by Molecular Beam Epitaxy

Abstract

We present II–VI wide bandgap semiconductor ZnSe and ZnSSe based blue-violet avalanche photo-diode (APD) operation grown on GaAs substrate by molecular beam epitaxy (MBE). Because of highly improved crystal quality of the active layer, the ZnSSe APD reveals stable and high avalanche gain (G ≥ 60) in the blue-violet optical region under high field operation condition (E = 1.15 × 106 V/cm) at room temperature (RT). High electric field induced ionization coefficients α (for electrons) and β (for holes) are determined as a function of electric field strength E(V/cm); α(E) = 1.7 × 107 exp (—4.9 × 106/E) and β(E) = 3.7 × 106 exp (—4.0 × 106/E).