Characterization of electronic properties of InP(100) surfaces from computer-aided analysis of photoluminescence

The surface state density distributions NSS(E) on the InP surface were determined by employing a rigorous computer analysis of the dependences of the band-to-band photoluminescence efficiency YPL versus excitation light intensity F. Experimental YPL–F spectra, taken from the literature, were obtained for the n-InP (100) surface after chemical polishing and ion bombardment. Theoretical Y PL–F curves were calculated using a numerical simulator which takes into account all bulk and surface recombination processes. The NSS(E) distributions were determined for both surfaces from the best fit to experimental data by applying a procedure based on genetic algorithm. An increase in NSS(E) after ion bombardment was attributed to the surface disordering. The behaviour of the effective surface recombination velocity and quasi-Fermi levels for electrons and for holes versus F was also analysed.