Dislocation-independent Mobility in Lattice-Mismatched Epitaxy: Application To GaN

Abstract Lattice-mismatched epitaxy produces a high concentration of dislocations ( N dis ) in the interface region, and this region is often highly conductive, due to donor ( N D ) decoration of the dislocations. Here we show that a simple postulate, N D = α ( N dis / c ), where c is the lattice constant and α a constant of order 1–2, predicts a nearly constant low-temperature mobility, independent of N dis . This prediction is experimentally verified in GaN grown on Al 2 O 3 , and is also applied to other mismatched systems.