Low spin density amorphous hydrogenated germanium prepared by homogeneous chemical vapor deposition

Structural [nuclear magnetic and electron spin resonance (ESR), infrared spectroscopy], optical (absorption, photoacoustic, photoluminescence), and electrical data are presented for amorphous hydrogenated germanium (a-Ge) prepared by homogeneous chemical vapor deposition (HOMOCVD). Like HOMOCVD prepared amorphous hydrogenated silicon, these a-Ge materials exhibit very low ESR spin densities and systematically varying optical gaps and hydrogen contents. Nevertheless, the material displays no subband gap photoluminescence and minimal photoconductivity, suggesting that a spinless defect may ultimately limit the device application of all types of a-Ge and a-(Ge,Si) films.