Investigation of the electron non-radiative transition in GaInNAs/GaAs single quantum well structures by using a piezoelectric photothermal spectroscopy

Piezoelectric photothermal spectroscopy (PPTS) measurements were carried out at a room temperature for GaInNAs single quantum well structures, with the thicknesses of 10, 7, 5 and 3 nm. The exciton contribution was clearly observed and was superimposed on the two-dimensional band-to-band transition. The thickness dependence of the PPT signal peaks was well understood by the quantum mechanical consideration. The decrease of the well thickness results in the decrease of the quantized energy levels and the exciton binding energy. The present results showed that the new developed PPT methodology was a unique and a powerful tool for investigating the optical absorption spectra of extremely thin quantum well structures.