ON THE CORRELATION BETWEEN DRAIN AND GATE CURRENTS AND LIGHT-EMISSIONIN GAAS PHEMTS BIASED IN THE IMPACT IONIZATION REGIME

In this work we investigate, by means oi electrical and both spectral and integral electroluminescence measurements, the light emission mech anisms in AlGaAs/InGaAs/GaAs pseudomorphic HEMTs biased at high drain voltage. Under these conditions impact ionization and light emission t ake place due to hot electrons. We examine the distinctive features oi the light spectra (in particular, using a high-resolution monochromat or the spectrum peak is shown to possess a fine structure due to quant ized levels oi the InGaAs channel), their respective temperature and b ias dependence, and by means of physical considerations and a study of the correlation between tile light intensity and the device currents we speculate on the physical mechanisms giving rise to photon emission in the different energy ranges.