Showing papers on "Amorphous silicon published in 1971"

Structural model for amorphous silicon and germanium

Abstract: A model for amorphous germanium and silicon has been constructed using the random network concept. Each atom has a first coordination number of four, and only a small variation in the nearest neighbor distance is allowed. Non-crystallinity is due to variations in the tetrahedral bond angle and rotations about bonds. No difficulty was encountered in continuing to make the model larger and no difference in structure between the central and outer regions could be observed. The radial distribution function and the density of the model agree well with recent measurements.

Amorphous silicon film as a uv filter

Abstract: There is disclosed the use of a thin amorphous silicon film as a narrow-band rejection filter which is used either as a mask to UV light in semiconductor device processing or is used as a protective shield for solar cells which overheat in the presence of ultraviolet light.

Enhanced diffusion and electrical properties of ion implanted silicon.

Abstract: Indium and antimony were implanted in silicon and concentration profiles have been measured by means of radioactivation analysis. Hall effect has also been measured. The difference between the concentration profiles in single crystal silicon and amorphous silicon has been investigated. It was observed that high temperature ion implanted indium shows no enhanced diffusion below 200 °C and that it shows temperature independent enhanced diffusion above 300 °C. Indium shows no enhanced diffusion in highly damaged region and the migration of indium seems to be terminated by trapping at defects. Enhanced diffusion of antimony seems to take place via vacancy.

An attempt to observe the double plasmon loss by electron spectroscopy

Abstract: The technique of electron energy loss has been applied to an investigation of the theoretical predictions of Ashley and Ritchie (1970) on the double plasmon excitation process. Electron energy loss spectra of evaporated silicon and aluminium films have been recorded at an incident electron energy of 60 keV and these spectra have been corrected for plural scattering effects. After this correction, no spectra exhibited a prominent loss in the region 31 to 33 eV, where the double plasmon loss would be expected. It is concluded that for amorphous silicon and polycrystalline aluminium films, the cross section for the double plasmon excitation is less than 0.02 of the cross section for the single plasmon excitation process.

Model for amorphous semiconductors predicts energy band gaps

Abstract: How do amorphous semiconductors get their energy band gaps? Experimental results over the past few years have shown that amorphous silicon and germanium films have gaps between valence and conduction bands that are similar to the gaps that exist when these substances are crystalline Efforts to justify these gaps theoretically bog down because of the lack of Bragg planes in amorphous substances; energy band gaps in crystals arise because of scattering by the planes, and most solid‐state theorists have assumed that some kind of periodicity is needed to explain gaps