Study on the Quantum Confinement of Photo-Generated Carriers in Quantum Wells

According to the classical theory, multi-quantum wells (MQWs) have quantum confinement effect on photo-generated carriers, which limits its application in light-to-electric devices. However, relevant experiments showed that a large proportion of photo-generated carriers can escape from MQWs sandwiched in the p-type layer and n-type layer (PIN structure), but not in the NIN structure. In order to study this phenomenon carefully, we applied positive and negative bias to an NIN structure respectively to simulate the PIN structure. By analyzing the photoluminescence (PL) spectra, we observed a weak escape behavior of photon-generated carriers among QWs in NIN structure. The experiment results indicate that strong electric field could drive carriers to escape from QWs rather than relaxation and recombination, while in NIN structure the inhomogeneous distribution of the electric field intensity reduces the carrier transport efficiency. The further study will give new ideas to design and produce photoelectric devices.

Automated summary

According to classical theory, multi-quantum wells (MQWs) have been limited in their application in light-to-electric devices due to the quantum confinement effect on photo-generated carriers. However, experiments have shown that a significant proportion of carriers can escape from MQWs in the PIN structure, but not in the NIN structure. To study this phenomenon, we applied positive and negative bias to an NIN structure to simulate the PIN structure. Analysis of the photoluminescence spectra revealed a weak escape behavior of carriers in the NIN structure. The results suggest that a strong electric field can drive carriers to escape from MQWs, while the inhomogeneous distribution of electric field intensity in the NIN structure reduces carrier transport efficiency.