Abstract:
Recently, the anomalous carrier transport in the quantum wells with the PN junction structures has been found experimentally, and the corresponding physical mechanism and the carrier transport model have been proposed. It is observed that the open circuit voltage or short-circuit current can be measured in the resonant excitation mode. Comparing the photoluminescence (PL) spectra of the two kinds of external circuits, it is found that the PL intensity decreased significantly under the short circuit condition. This suggests that the photogenerated carriers under the short circuit condition are not confined in the quantum well, but escaping from the junction region. However, this phenomenon of photocarriers escaping from the quantum wells is not found in the NN-type quantum well structure. Therefore, the effect of thermal excitation or tunneling is excluded to drive the carrier escaping from the quantum well. Based on this, the corresponding physical mechanism and carrier transport model are proposed. It is concluded that photogenerated carriers can escape from the quantum well directly under the built-in electric field of PN junction, and the radiative recombination luminescence occurs after the carrier escape process.
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