Optical Properties of Strained CdTe/ZnTe Pyramidal Quantum Dots

Abstract

A brief review of established methods shows that only with the Berthelot technique is it possible to see a finite volume of liquid in sustained mechanical tension. A short discussion of the practice and theory reveals two uncertainties with the conventional technique : that of the determination of a true filling temperature, and the influence of compliance by the glass on the tension developed. A description is then given of a modified apparatus with which these difficulties do not arise. The tube is formed into a coil which deflects sufficiently to indicate internal pressure or tension, and by monitoring these deflections with a distance meter a record of pressure/ tension against temperature can be made. The course of a typical run is shown from which the excess pressure, filling temperature and limiting tension may all be estimated with much greater precision than befoie. The orders of magnitude of the results obtained are indicated, and a possible influence of non-uniform gaseous supersaturation is suggested.

On Optical Properties of CdTe/ZnTe Quantum Rings

“…It is interesting to note that the gain spectra shows single peak, in contrast to the double peaks with unequal intensities for the cases of the strained pyramid QDs. 18,19) The redshift of the peak gain wavelength with increasing QR height is similar to that of the pyramid QD with increasing wetting layer. 19) In Fig.…”

“…As were previously demonstrated for CdTe/ZnTe QD heterostructures, [15][16][17][18][19][20] the size and material constituents of the wetting, the capping, and the substrate layers strongly influence on the strain distributions and subsequently on the energy structures. In here, we study how the size of QR affects the energy structure.…”

“…14) We recently analyzed how the structural elements such as the wetting layer and the mole fraction of QDs can affect the strain distribution and subsequently the optical properties, based on the linear elasticity theory of solids and the eightband k Á p Hamiltonian. [17][18][19][20] It was demonstrated that the optical gain peak on the shorter wavelength side was decreased with increasing wetting layer thickness and the gain peak on the longer wavelength side was nearly independent of the wetting layer thickness. 19) Similar characteristic behaviors are expected to occur in QR heterostrcutures.…”

“…In this paper, based on our numerical model for QD systems, [15][16][17][18][19][20] we study the optical properties of CdTe/ZnTe self-assembled QR as functions of the height and inner diameter with a finite element method (FEM) based on the linear elasticity theory of solids and the eight-band k Á p Hamiltonian. We find that the QR height significantly alters the bi-axial strain, while it has less effect on the hydrostatic strain.…”

“…The matrix element for the x-polarization is shown to be much larger than that of the z-polarization, in contrast to the results of the truncated QD heterostructure. 18,19) We study how the peak position of gain spectra can be either redshifted or blueshifted depending on the size of the QR heterostructure.…”