We report on the demonstration of light emission from hybrid CdZnO quantum-well light emitting diodes. A one-dimensional drift-diffusion method was used to model the expected band structure and carrier injection in the device, demonstrating the potential for 90% internal quantum efficiency when a CdZnO quantum well is used. Fabricated devices produced visible electroluminescence that was found to redshift from 3.32 to 3.15 eV as the forward current was increased from 20 to 40 mA. A further increase in the forward current to 50 mA resulted in a saturation of the redshift.

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The complex refractive indices of Cd x Zn 1-x O thin films were determined by transmission spectrophotometry. Transmission spectra were modeled from 375 nm to 800 nm for samples having cadmium concentrations ranging from 2% to 77%. The transparent and absorptive regimes were fitted separately by Sellmeier and Forouhi-Bloomer models, respectively. Real refractive indices of Cd x Zn 1-x O shift to higher values in the transparent region and the optical absorption edge shifts to longer wavelengths with increasing cadmium concentration. Spectroscopic ellipsometry was carried out on one sample from k = 190 nm to 1.8 lm. Comparison between the two methods shows that the results are in general agreement.

We report on the heteroepitaxial growth of high-quality single crystal cubic Zn x Mg 1-x O and Ni y Mg 1-y O thin films by radio frequency oxygen plasma-assisted molecular beam epitaxy (RF-MBE). Film compositions over the ranges x = 0 to x = 0.65 and y = 0 to y = 1 have been grown on lattice-matched MgO (100) and characterized optically, morphologically, compositionally, and electrically. Both of these ternary materials are shown to have bandgaps which vary directly as a function of transition metal (Ni or Zn) concentration. Optical transmission measurements of Ni y Mg 1-y O show the bandgap to shift continuously over the approximate range 3.5 eV (for NiO) to 4.81 eV (for y=0.075). Similarly, the bandgap of cubic Zn x Mg 1-x O is shifted from about 4.9 eV (for x = 0.65) to 6.25 eV (for x=0.12). Films exhibit good morphological quality and typical roughness of Ni y Mg 1-y O films is 5 Å while that of Zn x Mg 1-x O is less than 15 Å, as measured by atomic force microscopy (AFM). X-ray diffraction (XRD) is employed to confirm crystal orientation and to determine the films' lattice constants. Film compositions are interrogated by Rutherford Backscattering (RBS) and electrical characterization is made by room-temperature Hall measurements.