Dopant-atom-induced disorder in hydrogenated amorphous silicon: Raman studies

Raman scattering measurements on thin films of undoped and B- and P-doped hydrogenated amorphous silicon (a-Si:H) alloys have been reported. The doped samples indicate considerable concentration-dependent changes in the longitudinal vibrations as well as in the position and full width at half-maximum of the optical band relative to the undoped samples. These dopant-atom-induced changes in Raman spectra are attributed to the modification of hydrogen microstructure and consequently to the degraded short-range order. These changes are proposed to degrade the doping efficiency in a-Si:H alloys.