Optical Excitation Density Dependence Of Spin Dynamics In Bulk Cubic Gan

The influence of the optical excitation density on the electron spin dynamics is experimentally investigated in bulk cubic GaN by time-resolved magneto-optical Kerr-rotation spectroscopy. The nanosecond spin relaxation times in moderately n-doped beta-GaN decrease with increasing excitation density, though the effective lifetimes of the optically excited carriers are almost two orders of magnitude shorter than the spin relaxation times. This counterintuitive finding is explained by the heating of the electron system due to the excitation process. The spin relaxation times in degenerately n-doped beta-GaN are found to be independent of excitation density as the very high electron Fermi temperature completely dominates over carrier heating processes in this case. Published under license by AIP Publishing.