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

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 ZnCl2 as an n-type dopant source. Dark and illuminated I -V characteristics, as well as the spectral response are presented. Two tra nsport 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 curr ent density of 15 mA/cm(2), and a fill factor FF = 0.53, resulting in an ef ficiency close to 4%. The spectral response of the structure extends from t he band gap of GaAs to energies higher than that of the band gap of ZnSe, i n this high photon energy region being larger than that of a commercial p-i -n Si photodiode. (C) 1999 Elsevier Science B.V. All rights reserved.