Abstract
In this article we review the study of electron and hole transport in compensated a-Si by transient drift mobility techniques. The recent work of the Dundee group, extending over a wide range of compensated doping, provides detailed information on carrier/tail state interactions, the effect of the random potential fluctuations introduced by the dopants and the hopping transport through the donor centers. An explanation for the fundamental disagreement of these results with those of the Xerox group is given on the basis of new experimental data. The conclusions from the transport experiments are discussed and compared with recent ESR and LESR work on compensated a-Si.