Infrared and far-infrared absorption of B- and P-doped amorphous Si

Abstract

We present measurements of the infrared and far-infrared absorption spectra of B- and P-doped $a\ensuremath{-}\mathrm{S}\mathrm{i}(\mathrm{H})$. We have identified in these spectra local modes of the B-H and B-Si bands. The intrinsic infrared absorption of the Si-Si network is greatly enhanced by the presence of the dopants. Transverse effective charges are evaluated and discussed in terms of the bond-orbital model.