Light induced phenomena in microcrystalline silicon

Light induced phenomena in hydrogenated microcrystalline silicon (μc-Si:H). i.e., light induced electron spin resonance (LESR) and light induced defect formation are studied. A single resonance line with a g-value of 1.998 is induced by the hand gap light of c-Si (hv > 1.1 eV) at low temperatures of T < 80 K. It is suggested from the spin density and its temperature dependence that this center is a trapped electron at a shallow conduction band tail state of Si crystallites. The defect formation has been observed by the ESR after prolonged light exposure. The defect formation correlates with the surface oxidation. A surface band bending model due to the oxidation is proposed.