Observation of the photovoltaic effect in n-ZnSe/p-GaAs heterostructures

Abstract

We report the photovoltaic properties of an n-ZnSe/p-GaAs heterostructure. The n-type ZnSe films were grown by molecular beam epitaxy using Zn and Se effusion cells and ZnCl 2 as an n-type dopant source. Dark and illuminated I– V characteristics, as well as the spectral response are presented. Two transport mechanisms (recombination and tunneling) were observed in the dark I– V curves as a function of temperature. The photovoltaic parameters of the heterojunction were an open-circuit voltage of 500 mV, a short-circuit current density of 15 mA/cm 2, and a fill factor FF=0.53, resulting in an efficiency close to 4%. The spectral response of the structure extends from the band gap of GaAs to energies higher than that of the band gap of ZnSe, in this high photon energy region being larger than that of a commercial p–i–n Si photodiode.