Figure 5
Evolution of the PL intensity against temperature measured in different samples. (a) Integrated PL intensity of different bands in p-GaN/(111)Si sample: red spheres correspond to the total spectral integration, purple dots, green diamonds and orange pentagons correspond to (FE + D0X), I1 and I2 related transitions, respectively. Note the thermal equilibrium reached after 150 K. Inset: Arrhenius plot of the PL intensity, which corresponds to an activation energy about 21 meV that is close to the free exciton binding energy of bulk GaN. (b) Normalized PL intensity for our two porous GaN samples in comparison with the results reported by Zettler et al. for GaN nanowires with different diameters39. Dotted and solid lines are guides to the eyes.
