We report evidence for a population inversion between excited electron states of the quantum well of a GaAs‐AlGaAs double barrier resonant tunneling structure (DBRTS). The relative populations of the states are determined by photoluminescence spectroscopy of the tunneling electrons in the structure. When the DBRTS is biased at the fourth electron resonance, the population of the n=4 confined level is found to be greater than that of the n=3 state. We show that such a population inversion is consistent with a rate equation analysis of the relative populations of the two levels when electrons tunnel into n=4.
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