Measuring hot electron temperatures in semiconductors under high injectionlevels

One of the most widely used methods to measure the excess carrier temperatu re in semiconductors is super band gap time-resolved photoluminescence. We find that under high carrier injection levels the formalism commonly used t o extract the electron temperature using this method is erroneous due to th e neglect of the role of the quasi-Fermi levels. A method that can be used to obtain accurate carrier temperatures while taking into account the impor tant factors affecting the excess carrier concentration is proposed. The me thod is used to analyze time-resolved photoluminescence measurements perfor med on thin GaAs epilayers. It is found that the proposed method accurately corrects the apparent slow electron cooling frequently found in bulk semic onductors. (C) 1999 American Institute of Physics. [S0021-8979(99)05918-6].