Temperature dependence of fundamental band gaps in group IV, III–V, and II–VI materials via a two-oscillator model

Abstract

We perform numerical analyses of the temperature dependences of fundamental band gaps, Eg(T), and/or exciton peak positions, Egx(T), for a large variety of group IV, III–V, and II–VI (including wide band gap) materials using a two-oscillator model. This model assumes a fixation of the low-energy oscillator in the vicinity of the dominant TA peak, whereas the location of the high-energy oscillator is taken as an adjustable parameter depending on the relative weights of the contributions of short-wavelength LA and LO/TO phonons. The material-specific sets of empirical parameters have been estimated from fittings of measured E(T) dependences. The results indicate significant changes of the relative contributions of optical versus acoustical phonons from one material to the other. The degree of dispersion is found to increase significantly with contribution of low-energy acoustical phonons.

Effect of temperature on isotopic mass dependence of excitonic band gaps in semiconductors: ZnO

“…A more popular and significantly simpler theoretical approach to the temperature dependence of the band gap involves a two-oscillator approximation. 22,24,25 The approximation assumes that the lattice dynamics of the semiconductor can be described in a satisfactory manner by two harmonic oscillators, for instance, an average acoustic and an average optic mode.…”

Metastability of Band-Gap Energy in GaInNAs Compound Investigated by Photoreflectance

“…However, a detailed analysis shows that the phenomena related to nitrogen environment are not sufficient to explain the change in Varshni and B-E parameters. The postgrowth annealing, besides changes in nitrogen environment, leads to significant [33], b Ref. [20] reduction in the number of structural defects [24,34,35].…”

“…(2) and (3), respectively. The fit-determined parameters, E 0 (0), α, β, a B , and Θ B , together with literature data [33] are listed in Table. Significant differences in Varshni and B-E parameters are observed for the four different band gaps. Moreover, the literature data is rather poor in this field.…”

Type-II Superlattice for High Performance LWIR Detectors

“…Although the beta is interpreted as dependent on the Debye temperature of the semiconductor, no clear description has been defined in the available literature. For example, for a simple material such as GaAs it cannot even accurately describe measured data [6]. Where OCB represents the electron -phonon interaction, 6 H = ^°VK is the characteristic temperature representing the effective phonon energy on the temperature scale, the bandgap at 0 K is represented as E g (0K)= E H -#".…”

“…Where OCB represents the electron -phonon interaction, 6 H = ^°VK is the characteristic temperature representing the effective phonon energy on the temperature scale, the bandgap at 0 K is represented as E g (0K)= E H -#". [6] allowing an improved fit to experimental data of several bulk and designed semiconductors. In the high temperature range all three models are almost indistinguishable and are usually considered interchangeable for high temperature modeling [8].…”