Photoluminescence pressure coefficients ofInAs∕GaAsquantum dots

Abstract

We have investigated the band-gap pressure coefficients of self-assembled InAs/GaAs quantum dots by calculating 17 systems with different quantum dot shape, size, and alloying profile using atomistic empirical pseudopotential method within the "strained linear combination of bulk bands" approach. Our results confirm the experimentally observed significant reductions of the band gap pressure coefficients from the bulk values. We show that the nonlinear pressure coefficients of the bulk InAs and GaAs are responsible for these reductions. We also find a rough universal pressure coefficient versus band gap relationship which agrees quantitatively with the experimental results.We find linear relationships between the percentage of electron wavefunction on the GaAs and the quantum dot band gaps and pressure coefficients. These linear relationships can be used to get the information of the electron wavefunctions.

Ab initiocalculations of third-order elastic constants and related properties for selected semiconductors

“…12,14,15,16,17,18 In this paper, we perform ab initio calculations of the unknown third-order elastic constants in cubic nitrides. The nitrides are technologically important group of materials for which the nonlinear effects are particularly significant.…”

Optical transition in self-assembled InAs/GaAs quantum lens under high hydrostatic pressure

“…It is reported a significant decreasing in the hydrostatic pressure coefficient (PC) for InAs/GaAs QDs in comparison with bulk material. Different experimental works have proposed some explanations: non-uniform Indium distribution in the QDs 33 , pressure dependence of the effective masses and confined potential 32 , and the necessity to include a nonlinear strain distribution 26 and band-gap pressure dependence and finite barriers 34 . From the theoretical point of view some works have been devoted to explain the obtained low value of hydrostatic PC.…”

“…Photoluminescence (PL) measurement under high hydrostatic pressure has been proveed to be an effective tool for exploring the electronic structure and optical transitions in QDs 25,26,27,28,29,30,31,32 . It is reported a significant decreasing in the hydrostatic pressure coefficient (PC) for InAs/GaAs QDs in comparison with bulk material.…”

“…25, atomistic empirical pseudopotential method in Ref. 28 and atomistic valence-force field method in Ref. 27 were implemented.…”

Dependence of the band‐gap pressure coefficients of self‐assembled InAs/GaAs quantum dots on the quantum dot size

“…Here we present the results from photoluminescence experiments on a sample of coefficients of the transition energies as it exhibits up to nine QD subensembles, each with a different size. Only recently Luo et al [2] reported results from empirical pseudopotential calculations for many different dot geometries and found an almost linear dependence between the emission energy, which is a function of the dot size, and the pressure coefficients. Those are, however, heavy numerical calculations, where the physical origin of the observed effects is difficult to trace back.…”