Optical absorption, photoconductivity, and photoluminescence of glow-discharge amorphousSi1−xGexalloys

Low energy shifted photoluminescence of Er3+ incorporated in amorphous hydrogenated silicon–germanium alloys

“…SiO 2 substrate, the samples show an enhancement in the oxygen concentration with respect to the top layer, quite probably coming from oxygen atoms either sputtered or thermally diffused from the substrate, hence this emission may be originating from SiGeO x in analogy to the emission reported by von Roedern et al of a set of samples of amorphous a-Si 1Àx Ge x :H for several Si concentration. [12] In that work, they report that for Ge concentrations between 0% and 36% the photoluminescence of these samples falls in the range of 0.9-1.5 eV [12].…”

“…[12] Our experimental results suggest that this PL narrow band displays atomic characteristics that may be reflecting the resonance in energy that results in an energy transfer between some of the Er 3+ levels, participant in some ionic transitions, either the reported 4 S 3/2 ? 4 I 15/2 (or the unobserved 4 I 9/2 ?…”

The density of states in the mobility gap ofa-Si1−x Ge x films

“…Early studies of transport properties [5][6][7] suggest that, alloying Ge to a-Si, transport parameters such as mobility and minority carrier diffusion length decline rapidly. All these results are justifiable with an increase of midgap states.…”

Electrical Properties of Hydrogenated Amorphous Si1-xGexThin Films

“…Amorphous hydrogenated binary Si-Ge alloy films (a-Si1-x Ge:H) have recently been investigated extensively and are expected to be a useful optoelectronic material for λ > 700 nm [1][2][3][4][5]. Introduction of Ge reduces the optical gap below 1.8eV, typical for a-Si:H and better matches the optical gap for the solar radiation spectum.…”

“…Most of Si-Ge alloy films are deposited by the glow discharge decomposition of a gas mixture of SiΗ4 and GeH4 [1][2][3], [5]. However, this method has several drawbacks such as the poisonous and inflammable nature of the reactive gases and the poor control of the hydrogen content in the film.…”