PLASMA-DEPOSITED NONSTOICHIOMETRIC HYDROGENATED GERMANIUM SULFIDE A-GE1-XSX-H (X-LESS-THAN-0.3)

Hydrogenated amorphous germanium-sulfur alloys were prepared by PCVD f rom H-2, GeH4 and SF6. Addition of sulfur reduces the hydrogen concent ration in the films by a factor of two and decreases the activation en ergy of the conductivity from 0.5 eV for a-Ge:H to 0.14 eV and is rela ted to n-type doping. Sulfur incorporation significantly improves the quality of films prepared at the unpowered electrode: the eta/mu-produ ct increases by three orders of magnitude to 10(-6) cm(2) V-1, the ten sile stress is reduced and there is no significant post-oxidation unde r ambient pressure. The IR-absorption band around 360 cm(-1) related t o Ge-S bond stretching vibrations, increases proportional to sulfur co ncentration. Radial distribution functions show a continuous reconstru ction of the Ge network with sulfur.