Abstract
An experimental investigation of the unique photocurrent spectra of p-i-n photodiode with a GaAs/AlAs/AlGaAs quantum well and bulk GaAs absorption regions at 77 K is presented. The results showed that the excitonic absorption transitions in the quantum wells create sharp dips in the featureless bulk background spectra for low reverse bias voltages, while the spectra at high reverse biases show normally expected features with sharp quantum-confined excitonic absorption peaks superimposed on the background absorption. Furthermore, we found that the spectral features are very sensitive to the incident light intensity. These remarkable results are explained in terms of competition between the carrier escape rate from the quantum well region and the carrier generation rate in the bulk GaAs region, as well as by partial screening induced by carriers accumulated in the quantum well region.
Published Version
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