Study of the thermo-optic effect in hydrogenated amorphous silicon and hydrogenated amorphous silicon carbide between 300 and 500 K at 1.55 mu m

The thermo-optic coefficients of hydrogenated amorphous silicon (a-Si:H) an d hydrogenated amorphous silicon carbide (a-SiC:H)-two of the main amorphou s semiconductors in optoelectronics-have been measured and critically analy zed in the practical device operation temperature range 300-500 K, at the c ommunication wavelength of 1.55 mum. The experimental data have been fitted using a single-oscillator model that takes into account the shape of the e psilon (2) spectrum of the amorphous materials. In particular, for a-Si:H, the extracted parameters significantly extend, and are consistent with, the few data reported in the literature; an interesting analogy with crystalli ne silicon is also found and discussed. Complete results for a-SiC:H are fi nally reported. (C) 2001 American Institute of Physics.