Growth and optical characterization of single quantum well structure of submonolayer ZnS/ZnTe

Single quantum wells of submonolayer ZnS/ZnTe were grown between ZnTe layers using hot wall epitaxy method with fast-movable substrate configuration. As ZnS well widths decrease from 1 to 0.15 monolayer, the photoluminescence peaks shift to higher energies from 2.049 to 2.306 eV, and the photoluminescence intensities increase. As ZnS well width decrease, the PL spectra show the lower-energy tails and consequently the increased PL FWHMs. This is a result of a convolution of two PL peaks from two-dimensional and zero-dimensional quantum islands, supported by a still lived lower-energy peaks of zero-dimensional quantum islands above 50 K. The energy shift in the power dependence of photoluminescence spectra is proportional to the third root of the excitation density. These behaviors can be described by the formation of submonolayer type-II ZnS/ZnTe quantum well structure, and the coexistence of two-dimensional and one-dimensional islands in ZnS layers.