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Investigation of the Electron Nonradiative Transition in Extremely Thin GaInNAs/GaAs Single Quantum Well by Using a Piezoelectric Photothermal Spectroscopy

Room-temperature piezoelectric photothermal spectroscopy (PPTS) measurements were carried out for the single-quantum-well (SQW) structures of GaInNAs. Four as-grown samples with thicknesses of 10, 7, 5 and 3 nm were used to investigate the quantum confinement effect in the SQW. The exciton contribution was clearly distinguished from the two-dimensional step like band-to-band transition. The thickness dependence of PPT signal peak energy were well understood by quantum mechanics. The decrease in well thickness results in increases in quantized energy level and exciton binding energy. The present results showed that the newly developed PPT methodology is a unique and powerful tool for investigating the optical absorption spectra of extremely thin quantum well structures.