Strain Compensation in Single ZnSe/CdSe Quantum Wells: Analytical Model and Experimental Evidence

Abstract

The lattice mismatch between CdSe and ZnSe is known to limit the thickness of ZnSe/CdSe quantum wells on GaAs (001) substrates to about 2-3 monolayers. We demonstrate that this thickness can be enhanced significantly by using InGaAs pseudo substrates, which generate alternating tensile and compressive strains in the ZnSe/CdSe/ZnSe layers resulting in an efficient strain compensation. This method enables to design CdSe/ZnSe quantum wells with CdSe thicknesses ranging from 1 to 6 monolayers, covering the whole visible spectrum. The strain compensation effect is investigated by high resolution transmission electron microscopy and supported by molecular statics simulations. The model approach with the supporting experimental measurements is sufficiently general to be also applied to other highly mismatched material combinations for the design of advanced strained heterostructures.

Advanced material system for the design of an intermediate band solar cell: Type-II CdTe quantum dots in a ZnCdSe matrix

“…By using Eq. ( 2), which relates the out of-planelattice parameter to the elastic constants of the SL, we can accurately calculate the thickness and strain of the QDs for this sample 17 :…”

MBE Growth and Optical Properties of Isotopically Purified ZnSe Heterostructures

“…The latter make wide-gap II/VI semiconductors feasible for low operating power, optically pumped device applications such as low-threshold microdisk lasers in the visible range. − More recently, inter-sub-band absorption devices in the infrared range , as well as single photon sources in the visible range − were demonstrated. Besides such devices, the excellent epilayer properties of ZnSe − particularly feature basic research studies such as exciton–polariton coupling − or electron- , and nuclear-spin dynamics in ZnSe and related materials grown on GaAs substrates.…”