The dislocation origin and model of excess tunnel current in GaP p-n structures

An excess tunnel current in GaP epitaxial nondegenerate p-n junctions on Ga P and Si substrates was studied. An important experimental result is that t he slope of exponential current-voltage (I-V) characteristic (in lnI-V coor dinates) is independent of the width of the space-charge region, i.e., on n - and p-region doping levels. This fact is unexplained by existing models. A dislocation shunt model based on multihop tunneling through a dislocation line, which may be considered as a chain of parabolic potential barriers, is proposed. The density of dislocations predicted by this model is in agre ement with the transmission electron microscopy (TEM) observations. (C) 200 0 MAIK "Nauka /Interperiodica".