Electronic structure of compensated dopants in hydrogenated amorphous silicon

The authors use first principles pseudopotential method to study the electronic structures of compensated dopants in a realistic model of hydrogenated amorphous silicon. Boron and phosphorus atoms are treated as dopants. Two sites in the gap are identified as the boron-phosphorus pair related states. The lower energy state, strongly localized around the boron atom, is obtained when the atom has a hydrogen atom as a nearest neighbor. The local environment does not affect the localization feature of the state. Other environment around the boron atom cause the charge distribution to be more extended in space. The higher energy state having its charge around the phosphorus atom does not show, strong localization at the phosphorus atom