Experimental study of hydrostatic and shear deformation potential inGa1−yInyNxAs1−xalloys using a piezoelectric photothermal spectroscopy

Abstract

The band gap and exciton binding energies of dilute nitride ${\mathrm{Ga}}_{1\ensuremath{-}y}{\mathrm{In}}_{y}{\mathrm{N}}_{0.012}{\mathrm{As}}_{0.988}$ films with the thickness of $100\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ were determined as a function of indium composition for investigating the effect of strain on the electronic band structure. The high sensitive piezoelectric photothermal (PPT) methodology was used for measuring the optical absorption spectra. The fitting analysis was carried out to eliminate the influence of exciton and to determine precisely the band gap energy using the three dimensional direct allowed transition models with the Voigt function as a convolution profile. Comparing experimental result with the theoretical prediction for the strain free structures, the hydrostatic and shear deformation potentials were determined as $\ensuremath{-}7.0$ and $\ensuremath{-}1.7\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$, respectively. We found that the shear deformation potential is almost the same as that for GaAs, conflicting to the reported results for GaNAs. The results demonstrated that the present PPT method is worth for investigating the effect of strain on the electronic structures of the dilute nitride semiconductor thin film structure.