Electronic states of a-Si:H upon Cs adsorption and deep defect creation

The evolution of the near-surface states of a-Si:H is investigated as a function of Cs adsorption. At low coverage there is a large increase of band bending with a creation of a large number of negatively-charged deep states inside the sample. At high coverage most of the Cs charge remains trapped at the interface producing a large decrease of the photothreshold.