Temperature dependence of the energy gap of zinc-blende CdSe and Cd1−xZnxSe epitaxial layers

Abstract

The temperature dependence of the energy gap of zinc-blende CdSe and Cd1−xZnxSe has been determined over the entire range of composition from optical transmission and reflection measurements at temperatures between 5 and 300 K. The experimental results can be expressed by the following modified empirical Varshni formula, whose parameters are functions of the composition x: Eg(x,T)=Eg(x,0)−β(x)T2/[T+γ(x)]. Eg(x,0) exhibits a nonlinear dependence on composition, according to Eg=Eg(0,0)(1−x)+Eg(1,0)x−ax(1−x). The parameters β(x) and γ(x) can be expressed by β(x)=β(0)(1−x)+β(1)x+bx(1−x) and γ(x)=γ(0)(1−x)+γ(1)x.

Properties of PbS: Ni2+ Nanocrystals in Thin Films by Chemical Bath Deposition

“…The experimentally observed E g values for the shift indicated an alloying between nanocrystalline PbS. Such increase has been observed by other authors [19,20]. The E g for doped samples in the 2.4-3.8 eV range the large experimentally observed E g in the nanoparticle films theoretically estimated (using Vegar ds law) E g for bulk shows the extent of quantum size effect in the nanoparticle films.…”

Structural phase control of CdSe thin films by metalorganic chemical vapor deposition

“…1B. When the flux ratio of H 2 Se and DMCd was changed to another value (1.0 Â 10 À4 mol min À1 /3.51 Â 10 À6 mol min À1 ) while the growth temperature was kept at 360 1C, only an emission peak at 1.74 eV was observed in sample C. For hexagonal CdSe, the near-band-edge (NBE) emission at room temperature is about 1.738 eV [13]. Therefore, the emission peak at 1.74 eV in sample A is attributed to the NBE emission of hexagonal CdSe, and sample C is a typical hexagonal CdSe thin film.…”

Optical properties of Zn0.5Cd0.5Se thin films grown on InP by molecular beam epitaxy

“…The Varshni's fit yields E 0 ¼ 2:175 eV; a ¼ 0:37 meV=K and b ¼ 141 K (Table 3). [29]. The band gap energy of Zn 0.5 Cd 0.5 Se is determined over the entire temperature range by adding the exciton binding energy (27.2 meV) to the energy of the exciton absorption.…”