Samples of n-type semiconducting material were changed to p-type by means of short-term annealing at 700C. Further annealing for longer times led to a second conduction-type conversion which changed the material back to n-type; but with a much higher resistivity. These conversions indicated the formation of both acceptor and donor defects, and the progressive variation of their relative concentrations, during annealing.

Thermally Induced Conduction Type Conversion in n-Type InP S.Fung, Y.W.Zhao, C.D.Beling, X.L.Xu, N.F.Sun, T.N.Sun, X.D.Chen: Journal of Applied Physics, 1999, 86[4], 2361-3