Various Trap States at SiGe-SiO2 Interface Formed by a Pulsed Laser

We report fabrication of low-dimensional structures in air by a pulsed laser on SiGe alloy samples in which different oxide structures are formed by laserirradiation and annealing treatment. The micro-structures on SiGe are more complex than those on Si. A series of photoluminescence (PL) emission is observed due to various trap states at the SiGe-SiO2 interface formed under different preparing conditions. The peak centre of PL emission exhibits red-shift from Si to SiGe because of narrower gap. A model for explaining the PLemission is proposed in which the trap states of the interface between some oxide and SiGe play an important role.