Spatially resolved photoluminescence (PL) measurements have been performed on GaAs/GaInAs/GaAlAs pseudomorphic high electron mobility transistors to determine the local temperature on both sides of the gate with spatial resolution of about 1 μm and temperature resolution better than 1 °C. This local temperature is deduced from the energy shift of one of the peaks in the PL spectra. Asymmetry in the temperature distribution between the drain and source sides is observed. The experimental temperature values have also been compared with predictions from an analytical model to determine the thermal resistance in these devices.

The technique of spatially resolved photoluminescence (PL) spectroscopy was used to determine the local channel temperatures on GaAs/GaInAs/GaAlAs pseudomorphic high electron mobility transistors. By focusing a laser beam onto the different regions of the DC-biased transistor, it is shown that the channel temperature can be determined from the energy shift of one of the peaks in the PL spectra, with a spatial resolution of about 1 pnm and a temperature resolution in the order of 1 'C. In particular, an asymmetry in the temperature distribution between the drain and source sides is observed. Using this approach, detailed temperature maps of the devices were obtained, as a function of the gate-source voltage VGS. These experimental temperature values are also compared with predictions derived from an analytical model of the thermal resistance in these devices.