At lower temperatures, the higher mobility of electrons in gallium arsenide makes this material the more attractive circuit component. Unfortunately, when n-type AlGaAs semiconductors are cooled in the dark, the carriers are frozen out by a self-compensation mechanism, and their desirable electronic properties are lost. The nature of the mechanism of self-compensation, the so-called DX phenomenon, is a matter of current controversy. One model (D-no-X) views the effect as intrinsic to the donors themselves, and hence an absolute deterrent to low-temperature applications of III-V semiconductors. The other model identifies the process as defect-driven and hence avoidable, at least in principle. It is clear that resolution of the problem is crucial to the future development of high-performance III-V semiconductors. We propose to resolve the DX problem by using Mossbauer spectroscopy to obtain information about the solid state electronic environment of dopant muclei in AlGaAs semiconductors.
