Heterojunctions have been fabricated between CdSe films made by vacuum
evaporation and amorphous hydrogenated Si films deposited by plasma d
ischarge. With adjusted conditions, junctions of good rectification ra
tios have been produced (1000:1 at 2 V), although showing significant
interface states. The band offsets were determined by an internal phot
oemission technique as 0.06 eV for the valence bands and 0.02 eV for t
he conduction bands. A small unoptimised solar cell gave near 7% effic
iency.