High response photodiodes based on Be-chalcogenides

Be-containing II-VI semiconductors are promising high-band gap materials fo r optoelectronic devices. Here we present the fabrication and investigation of p-i-n photodiodes based on these materials. The diodes are grown on p-G aAs, and show low dark current. A p-doped BeTe blocking layer has been used in order to reduce the dark current. In addition, there is a low sensitivi ty in the visible range because the BeMgZnSe-layers of our structure with a bandgap of 2.8 eV are insensitive to wavelengths above 450 nm. We present measurements of the reverse bias photo current as a function of wavelength. The high-quantum efficiency of 65% at around 430 nm makes the device suita ble for applications in the field of near-UV radiometric measurements. (C) 1999 Published by Elsevier Science B.V. All rights reserved.