Measuring junction temperature of GaAs solar cells using pulse-width modulation photoluminescence

A photoluminescence (PL) technique is presented to measure the junction temperature of GaAs solar cells. The technique utilizes the pulse-width modulation of excitation laser and the temperature dependence of PL spectra. The apparent change of PL energy on duty cycle can be advantageously used for the determination of the junction temperature. Varying the duty cycle from 10% to 75% causes an increase of 2.9 K in the junction temperature of GaAs solar cells. The carrier temperature of the junction layer was studied to confirm the result obtained from the pulse-width modulation PL.