Depth-resolved cathodoluminescence microanalysis of near-edge emission in III-nitride thin films

We describe an approach to assess the quality of III-nitride thin films usi ng depth-resolved cathodoluminescence (CL) microanalysis. In this procedure , the depth-resolved peak shift due to self-absorption of the near-edge CL emission is calculated using Monte Carlo simulation techniques and compared with measured peak shift values. A discrepancy between the experimental an d modeled data indicates the presence of an exciton peak shift due to strai n, near-edge defects, and alloy fluctuation. Depth-resolved peak shift anal ysis of the near-edge CL from an undoped 700 nm thick Al0.057Ga0.943N film grown on a (0001) Al2O3 substrate is presented to demonstrate the utility o f the method. (C) 2001 American Institute of Physics.