Comparison of some theoretical models for fittings of the temperature dependence of the fundamental energy gap in GaAs

Abstract

In this work we report on a comparison of some theoretical models usually used to fit the dependence on temperature of the fundamental energy gap of semiconductor materials. We used in our investigations the theoretical models of Viña, Pässler-p and Pässler-ρ to fit several sets of experimental data, available in the literature for the energy gap of GaAs in the temperature range from 12 to 974 K. Performing several fittings for different values of the upper limit of the analyzed temperature range (T max ), we were able to follow in a systematic way the evolution of the fitting parameters up to the limit of high temperatures and make a comparison between the zero-point values obtained from the different models by extrapolating the linear dependence of the gaps at high T to T = 0 K and that determined by the dependence of the gap on isotope mass. Using experimental data measured by absorption spectroscopy, we observed the non-linear behavior of E g (T) of GaAs for T > Θ D .

Built‐in elastic strain and localization effects on GaAs luminescence of MOVPE‐grown GaAs–AlGaAs core–shell nanowires

“…We ascribe the main peak and the weak shoulder to a bound exciton line, and to an impurity recombination band, respectively. Figure 3 shows the dependence of the peak energy as function of temperature: in the 7 -70 K temperature interval, the line emission strictly follows the temperature dependence of the energy bandgap expected for bulk GaAs [8], after accounting for a 10.5 meV energy difference. The emission can still be observed up to 120 K, but above 70 K it progressively deviates (blue-shifts) from the expected values and starts to broaden, a behaviour which can be ascribed to the changing nature of the emission from exciton recombination to inter-band transition [9].…”

“…2. The black solid curve represents the energy‐gap of bulk GaAs $(E_{\rm G}^{\rm GaAs})$ 8; the red solid curve $(E_{\rm HH}^{\rm BE})$ is obtained from the former by accounting for a 10.5 meV energy reduction. The blue line is a guide for the eye.…”

“…where $E_{\rm G}^{\rm GaAs} $ = 1.5191 eV is the bulk (unstrained) bandgap at 7 K 8, a and d are, respectively, the hydrostatic and shear optical deformation potentials, ν is the Poisson ratio for the 〈111〉 direction, and Δ 0 is the split‐off valence band. Values of a and d close to those of bulk GaAs were reported in Ref.…”

Concentrated PhotoVoltaics (CPV): Is it a real opportunity?

“…Thermal management. -When designing a concentrated photovoltaics module, great attention must be paid to the thermal management: thermal management of CPV modules is one of the most important parts of its technology: the efficiency of the solar cells used decreases linearly increasing its temperature, at a rate of −0.06%/K, due to electron-phonon interactions [9]. As in any solar cell, the efficiency of the cell is strongly dependent on the cell's temperature [8].…”