Effect of threading dislocations on electron transport in In0.24Ga0.76N/GaN multiple quantum wells

The effect of threading dislocations on electron transport in In0.24Ga0.76N /GaN multiple quantum wells has been studied by using transmission electron microscopy (TEM) and van der Pauw Hall effect measurements. From the cross -sectional TEM imaging, we observed the threading dislocations which "screw '' through the multiple In0.24Ga0.76N/GaN quantum well. From the Hall effec t measurement, we found that the Hall mobility decreases as the temperature decreases (mu similar to T-3/2) due to the threading dislocation scatterin g, and the Hall carrier concentration shows a transition from conduction-ba nd transport to localized-state-hopping transport. The thermal activation e nergy of the residual donor level (probably Si! is about 20.2 meV. (C) 1999 American Institute of Physics. [S0003-6951(99)02415-8].