Glow Discharge Amorphous Silicon Research Articles

AC conduction of the heavily doped glow discharge amorphous silicon films

Temperature and frequency dependence of ac conduction of relatively heavily doped GDa-Si films are reported. These ac conduction show activation type conduction and these activation energy E a change with frequency. Effect of annealing on ac conduction is also discussed.

Laser annealing of glow discharge amorphous silicon

Glow discharge amorphous silicon layers have been annealed using a Q-switched ruby laser. The properties of the annealed films were studied as a function of laser energy by means of electron microscopy, photoluminescence and infra-red absorption. The changes in structure, hydrogen content, band-gap and density of states in the annealed layers are discussed. It is found that there are considerable similarities between the amorphous and the annealed material.

Effect of substrate temperatures and annealing on optically detected magnetic resonance in glow-discharge amorphous silicon

Optically detected magnetic resonance experiments have been performed at 2 K in glow-discharge amorphous silicon with different substrate temperatures. Effects of annealing and illumination on ODMR have been examined. A broad line is interpreted in terms of a three-centre bond model.

The Fermi level position in doped amorphous silicon

The shift of the Fermi energy with substitutional doping has been determined for glow-discharge amorphous silicon films by photoelectron spectroscopy. The values so obtained for n- and p-type specimens are in good agreement with the shift expected from the activation energy of the electrical conductivity and confirm that the Fermi level can be moved throughout most of the mobility gap of amorphous silicon. The data also show that the surface-state density at the Si-SiO2 interface is extremely low, so that information from field-effect experiments should be representative of the bulk states.

Electronic density of states in discharge-produced amorphous silicon

The localized state density distribution in the mobility gap of glow-discharge amorphous silicon has been determined from capacitance-voltage characteristics for metal/oxide/amorphous silicon (MOS) structures. This new method provides a smooth distribution of localized states throughout the mobility gap. The density of states increases from a minimum of the order of 1016 cm−3 eV−1 near midgap to more than 1018–1019 cm−3 eV−1 within 0.2 eV of the band edges.

Determination of Localized State Density Distribution in Glow Discharge Amorphous Silicon

A new method to determine the electronic density of states in glow discharge amorphous silicon has been applied. The analysis of capacitance-voltage characteristics of metallic gate/SiO2/amorphous silicon (MOS) structures provides the U-shaped gap state distribution with a minimum density of about 1017 cm-3 eV-1 near midgap. The density of tail states at 0.4 eV from both the valence and conduction band is of the order of 1018 cm-3 eV-1. The present results are in disagreement with those previously determined from the field effect technique. Possible explanations for this discrepancy are discussed briefly.

Quantitative analysis of hydrogen in glow discharge amorphous silicon

We report measurements of the hydrogen concentrations and densities of amorphous silicon films prepared from glow discharge plasmas of silane. Quantitative results are obtained from the resonant nuclear reaction 15N+1H→12C+4He+γ by counting the emitted γ rays. Mass spectrographic analysis of the gases evolved upon heating are also used to estimate the relative hydrogen concentrations for different preparation conditions. Comparisons are given to previously reported infrared absorption results and to electron microprobe estimates.