Persistent behaviour of 2DEG in single /spl delta/-layers

The persistent light-induced changes in InP sulphur doped single /spl delta/-layers were investigated experimentally by the magnetotransport methods. It was shown that in these highly disordered two-dimensional structures the observed behaviour is controlled by the sulphur-related DX-centres while the Fermi level of the sample as a whole is stabilised by the substrate background.