Pressure‐induced increase of exciton–LO‐phonon coupling in a ZnCdSe/ZnSe quantum well

Abstract

The possibility of pressure-induced increase of exciton-LO-phonon coupling in ZnCdSe/ZnSe quantum wells is studied. The ground state binding energies of the heavy hole excitons are calculated using a variational method with consideration of the electron-phonon interaction and the pressure dependence of the parameters. The results show that for quantum wells with intermediate well width, the exciton binding energy and the LO-phonon energy may coincide in the course of pressure increasing, resulting in the increase of exciton-LO-phonon coupling. It is also found that among the pressure-dependent parameters, the influence of the lattice constant is the most important one. The changes of both the effective masses and the dielectric constants have obvious effects on the exciton binding energy, but their influences are counterbalanced.

Multi-phonon (percolation) behavior and local clustering of CdxZn1−xSe-cubic mixed crystals (x ≤ 0.3): A Raman–ab initio study

“…[5][6][7] As is well known, the electron-phonon scattering processes adversely affect the optical and transport properties of electrons in semiconductors. [8][9][10] Therefore, when dealing with such a complex semiconductor system as a mixed crystal, it is of prime importance to elucidate the nature of its phonon-mode behavior. This is still an open issue in the case of Cd x Zn 1−x Se, as detailed below.…”

Optimization of growth conditions of type-II Zn(Cd)Te/ZnCdSe submonolayer quantum dot superlattices for intermediate band solar cells

“…6(b)] similar to sample A, demonstrating the type-II nature of the multilayered structure. The PL also showed phonon replicas, separated by the Zn 0.41 Cd 0.59 Se longitudinal-optical-phonon energy, 28 indicating small amounts of Te diffusion into the spacers and high crystalline quality of the QD SL. Hence, we were able to retain desirable optical properties of this material system, while improving the crystalline quality of the SL by strain balancing technique.…”

“…Furthermore, the room temperature bandgap corresponding to this buffer layer composition was evaluated to be 2.01 eV, using the known band bowing parameter. 5 This host bandgap is expected to increase by about 18 meV due to compressive strain in the system, calculated using deformation potentials 28 for this particular ternary alloy composition. Thus, introduction of a Cd-rich spacer in the SL lowered the spacer bandgap and brought it even closer to that of the ideal IBSC host, besides assisting in the growth of lattice matched SL.…”

Hydrostatic pressure effect on the electron mobility in a ZnSe/Zn 1- x Cd x Se strained heterojunction

“…where B 0λ is the bulk modulus, a 0λ is the lattice constant in the absence of strain. Both the biaxial lattice-mismatch-induced strain and the contribution from hydrostatic pressure to the total strain of the materials are given as [2,4]…”

“…[1] More recently, the shift of phonon frequencies and the variation of electron-phonon interaction were discussed to emphasize the strain effect. [4] On the other hand, as a useful tool hydrostatic pressure is widely used to probe and modulate the physical properties of the low-dimensional semiconductor systems. [5−8] The previous results showed that the hydrostatic pressure affects obviously the electronic effective mass, energy band gap, [5] dielectric constants, frequencies of optical phonons, [6,7] and the cyclotron mass of an electron with phonon effect, [8] etc.…”