Zq. Li et al., Photoluminescence study of Si doping cubic GaN grown on (001) GaAs substrates by molecular beam epitaxy, J CRYST GR, 227, 2001, pp. 420-424
The photoluminescence (PL) properties of Si-doped cubic GaN with different
carrier concentrations were investigated at room temperature. The epilayers
were grown on GaAs (0 0 1) by radio-frequency molecular beam epitaxy. It w
as found that when the carrier concentration is increased fi om 5 x 10(15)
to 2 x 10(18) cm(-3), the PL peak shifted towards low energy, from 3.246 to
3.227 eV, and the PL linewidth increased from 77.1 to 121 meV. The PL peak
shift is explained by the bandgap narrowing effect due to the high doping
concentration. The PL linewidth includes two parts: one is doping concentra
tion independent, which is caused by the imperfection of samples and phonon
scattering; the other is doping concentration dependent. We assign the sec
ond part to the broadening by the microscopic fluctuation of the doping con
centration. The experimental measurements are in good agreement with the mo
del. (C) 2001 Published by Elsevier Science B.V.