An a-Ge:H pin Solar Cell with High Red Efficiency

Abstract

Solar cells with pin structure were manufactured from pure hydrogenated amorphous germanium in order to obtain a red sensitive sub cell in a tandem stucture. Different deposition conditions were tested. A substrate temperature of 150°C and bombardment with ions of energy greater than 200 eV proved to be the best conditions. These conditions and a cell constructed with a p-SiC/p⁺-Si front contact and an i-layer thickness of round 0.3 µm yielded an overall cell efficiency under AM1 illumination of 2.5%. The external short-circuit collection efficiency for an illumination wavelength of 900 nm in this cell was 25% and increased to over 40% under a reverse bias voltage of -1V.