Layers of Si δ-doped In0.53Ga0.47As were grown, by means of molecular beam epitaxy, onto InP(001) substrates at temperatures of between 390C and 575C. Sub-bands which formed at the δ layer were examined by performing Hall and Shubnikov-de Haas effect measurements, together with self-consistent Poisson-Schrodinger modelling. It was found that, below a growth temperature of 525C, good agreement with the model predictions occurred. However, at temperatures above 525C, a decrease in the active doping level suggested the possible occurrence of surface aggregation, or reaction with ambient impurities. An appreciable surface segregation spread of the Si was found only for growth above 450C. There was some evidence that DX-like centers might be present, since their incorporation slightly improved the closeness of the fit to sub-band occupancies. Samples which were grown at 390C exhibited a strong persistent photoconductivity at low temperatures, and this was attributed to defect states in the InGaAs.

M.Zervos, A.Bryant, M.Elliott, M.Beck, M.Ilegems: Applied Physics Letters, 1998, 72[20], 2601-3