Time-integrated photoluminescence for sample B2. In this case, the frequency doubled output of the femtosecond Ti:Sapphire laser is tuned to 370 nm. Clearly, excitonic emission centered at 450 nm is present. In addition, sufficient overlap of the pump wavelength and the absorption edge of GaN was present. The yellow emission is from Ga vacancies within the n-doped material and served as a marker for the presence of carriers for screening of the built-in electric field.
© 1999 The Materials Research Society
