The phase transformation of amorphous silicon-aluminum thin films with 16 at.% and 30 at.% aluminum was characterized by TEM during an in-situ anneal at 500°C. No crystallization was observed in the samples having 16 at.% Al even after a 10 hour anneal at 500°C. In contrast, nucleation of crystallites was observed in the samples having 30 at.% Al after a 40 min anneal. The size of these crystallites grew during annealing. Single crystal regions were also observed and were identified as aluminum having <111> orientation.

The dependence of chemical composition, structure and optoelectronic properties of sputtered a-SiC:H thin films on substrate temperature, Ts, and hydrogen flow rate has been studied. The films are amorphous for the growth conditions used in this work. The chemical composition of the alloys is very little influenced by the Ts, whereas the hydrogen content and the optical absorption coefficient depends strongly on Ts and hydrogen flow rate.

Amorphous hydrogenated silicon-tin alloys have been prepared by if sputtering using a target of silicon with stripes of tin placed over the silicon surface in order to attain the appropriate silicon-tin composition. It is shown that for the composition range investigated, 0 ≤ 5 x ≤ 0.51, the addition of Sn moves the conduction band edge, thereby closing the optical band gap. The dependence of Eg on x can not be described by a single linear relationship. Sn also creates dangling bonds which further increase the material disorder. The electrical dc dark conductivity increases less than expected with increasing Sn content based on a simple decrease in band gap. This and the temperature dependence of the dark conductivity suggest a transition from extented state free-carrier conduction to localized state hopping conduction. The bonding between Si and H competes with that of Sn and H. Photoluminescence measurements show the presence of defect state radiative recombination. Calculations of optical band gaps, using the Coherent Potential Approximation with diagonal disorder and the off-diagonal disorder being treated within the virtual crystal approximation, are in excellent agreement with the experimental results.