Microcathodoluminescence of impurity doping at gallium nitride/sapphire interfaces

We have used low-temperature cathodoluminescence spectroscopy (CLS) to prob e the spatial distribution and energies of electronic defects near GaN/Al2O 3 interfaces grown by hydride vapor phase epitaxy (HVPE). Cross sectional s econdary electron microscopy CLS shows systematic variations in impurity/de fect emissions over a wide range of HVPE GaN/Sapphire electronic properties . These data, along with electrochemical capacitance-voltage profiling and secondary ion mass spectrometry, provide a consistent picture of near-inter face doping by O diffusion from Al2O3 into GaN, over a range 100-1000 nm. ( C) 2001 American Institute of Physics.