A series of a-B films with substrate temperature Tsranging from 300 to 800°C and two series of a-B1-xSixfilms (0.1≤x≤0.9) with Ts= 460 and 620°C were prepared by LPCVD method. Optical absorption spectra of these films from visible to near infrared region are measured in order to study the influence of Tsand the effect of Si incorporation into boron. Functions for density of states are constructed to fit the curves. When Tsincreases from 300°C to 800°C, the optical gap of a-B films decreases from1.2 to0.8eV, while the width of the tail states decreases. It is found that Si incorporation into boron introduces additional sub-gap states.
ASJC Scopus subject areas
- Ceramics and Composites
- Electronic, Optical and Magnetic Materials