LUMINESCENCE IN a-Si:H

Abstract

Dangling bonds, as observed in ESR, act as both radiative and non-radiative recombination centers in a-Si:H. The luminescence properties of a-Si:H are therefore very sensitive to the presence of dangling bonds.Non-radiative recombination is shown to occur by electron tunnelling at low temperature and by diffusion and capture at high temperature. The evidence for a weak radiative transition of electrons trapped at dangling bonds is discussed. The h~minescence properties of doped and compensated a-Si:H are shown to be dominated by the changes in dangling bond density.Introduction. -The inclusion of a tew percent of hydrogen during the deposition of amorphous silicon leads to a material with good semiconducting properties. The effect of hydrogen is to reduce the density of states in the gap, which in turn allows effective doping and results in long carrier lifetimes. Another consequence of the reduced gap state density is that efficient

Silicon Porosification: Approaches to PSi Parameters Control

“…A great deal of work was then done in those years to probe the crystalline quality of PSi and the presence of strain or lattice distortions. Those structural studies were intensified after the first report on the visible light emission from PSi (Canham 1990) because some explanations for this spectacular effect were based on previously known systems, like hydrogenated amorphous silicon (a-Si:H) in which light emission had been clearly observed and studied (Street 1984). Therefore, for some time, PSi structure has been deeply investigated in order to ascertain if its emission could be in some way related to the presence of an amorphous phase.…”