Retarding crystallization of CVD amorphous silicon by alloying

Abstract

Amorphous silicon holds considerable promise as a photothermal absorber, but high-temperature-induced crystallization limits its usefulness. To attempt to retard the crystallization, we produced CVD a-Si films alloyed with C, N, B, or Ge. These films crystallized differently than did the non-intentionally doped amorphous material. The crystallization temperature was increased from 680 C to 950 C for 18 at.% C-alloyed a-Si, and even then more than 10 hours were required for crystallization. This retardation of crystallization gives alloyed a-Si absorbers sufficient life expectancy for converters operating at temperatures up to 700 C.