Photoluminescence of CdHgTe based nanoheterostructures

We have studied the photoluminescence (PL) spectra of Cd _x Hg_{1 − x} Te/Cd _y Hg_{1 − y} Te nanohetero-structures grown by molecular beam epitaxy on CdTe/ZnTe/GaAs substrates. The width of potential wells in the structures was varied within d = 12−200 nm and the material composition was changed within x ∼ 0.25–0.40 in the well and y ∼ 0.68–0.82 in the barrier layers. The PL spectra of samples with d ≤ 33 nm exhibit transitions between quantum confinement levels. The samples with d > 50 nm display the PL due to excitons localized on composition fluctuations, which is characteristic of Cd _x Hg_{1 − x} Te epilayers with thicknesses above 3 μm. It is established that the exciton PL band in Cd _x Hg_{1 − x} Te exhibit broadening that is determined both by stochastic fluctuations of the composition and by its macroscopic inhomogeneities.