The quantum confinement effect observed in the multiple quantum wells Mg0.27Zn0.73O/ZnO

Dimensional effects in exciton and defect-related luminescence of ZnO-based step quantum wells

“…Figure 5 represents the experimental and calculated dependences of the exciton peak FWHM on L W for Mg 0.15 Zn 0.85 O/Cd 0.05 Zn 0.95 O. It is visible that the experimental dependence is well described by the calculated model given in work [13]. The initial 60 meV peak width caused by native defects and nonuniform distribution of cadmium concentration was specified at the construction of the calculated dependence.…”

“…In this case it is the thickness of the Cd 0.05 Zn 0.95 O layers. The dashed line corresponds to the calculated dependence of the energy of 1e − 1 h transition in a single Mg 0.15 Zn 0.85 O/Cd 0.05 Zn 0.95 O QW on the well width L W [13]. The values of effective masses of an electron m e and a hole m p for the active and barrier layers [14,15], as well as the electron concentration n used in the calculations are given in table .…”

“…The described above device and the pulsed laser deposition method were used to grow the Mg 0.27 Zn 0.73 O/ZnO, Mg 0.15 Zn 0.85 O/Cd 0.2 Zn 0.8 O and Mg 0.15 Zn 0.85 O/Cd 0.05 Zn 0.95 O multiple quantum wells (MQW) with the step change of the active layer thickness on c-sapphire substrates with the previously grown Mg 0.27 Zn 0.73 O buffer layers of 150 nm thickness. The method of deposition of the buffer layers providing a lattice matched growth of quantum wells is described by us in [13]. The number of quantum wells in each step was ten.…”

Room-temperature stimulated emission in two-dimensional MgxZn1−xO/ZnO heterostructures under optical pumping

“…The c-oriented sapphire substrate with an epipolished working surface is transparent in a wide spectral range, has a low coefficient of thermal expansion, and is relatively cheap. A detailed description of the MQW growth conditions is given in [8]. To study the optical properties of the low-dimensional structures the photoluminescence (PL) spectra were measured under excitation by a continuous He-Cd laser (λ exc = 325 nm, W = 20 mW) and a pulsed excimer KrF laser (λ exc = 248 nm, τ exc = 15 ns).…”

“…Registration of emission was performed at a wavelength near the peak maximum. The structural properties of the resulting quantum wells are described in detail in [8]. The photoluminescence spectra of MQW excited by continuous and pulsed lasers with a wide range of pump intensities were studied.…”