TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The A', B', x and y are selected to provide a semiconductor having a bandgap of not less than 1.9 eV. The composition is doped with p dopant selected from Au, Ag and K. The composition is doped with n dopant selected from Al, Ga and In. Preferred Film: The layer is an epitaxy layer. The substrate is selected from ZnO, III-nitride, sapphire, silicon, ScAlMg, or glass substrates.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Device: The semiconductor photovoltaic device further comprises a substrate of ZnO, the n-type doped semiconductor material disposed in contact with the substrate. The n/p-type semiconductor material comprises several n/p-type materials of the form (II) where x and y are varied incrementally from a first of the several n/p-type materials to a last of the several n/p-type materials to form a gradient of materials. The gradient of the materials is selected to provide lattice matching among adjacent materials in the several n/p-type materials. The A and B' are selected to provide a junction bandgap having efficient spectral response 1.5-2 eV. In (D2), the several semiconductor junctions are disposed on a substrate. A first of the several semiconductor junctions comprises n-type and p-type semiconductor materials to provide a first bandgap and a second of the several semiconductor junctions comprises n-type and p-type semiconductor materials to provide a second bandgap, the first bandgap being higher than the second bandgap. The first semiconductor junction is disposed on the substrate and the second semiconductor junction is disposed on the first semiconductor junction. The second semiconductor junction is disposed on the substrate and the first semiconductor junction is disposed on the second semiconductor junction. The device (D2), further comprises a resonant interband tunnel diode disposed between and in electrical communication with the first semiconductor junction and the second semiconductor junction. The junctions range from higher bandgap to lower bandgap zinc oxide films, where the topmost film is the higher or lower bandgap material. The ZnO tunnel diodes comprise delta doped regions of n and p type carriers deposited at 100-900 degrees C. The ZnO resonant interband tunnel diodes comprises compounds (I). The semiconductor photovoltaic device further comprises electrical contacts for connecting to an outside circuit, the contacts selected from silver, gold, nickel, and platinum, intermetallics, amalgams and/or eutectics of silver, gold, platinum, and nickel, oxides of silver, and nickel, and transparent conducting oxides including indium tin oxide, zinc indium oxide, zinc tin oxide or conducting n-ZnO doped with aluminum, and/or indium, and/or gallium. The device (D3) comprises optical emitter or LED, where the LED emits light at a wavelength of greater than 650 nm. The optical emitter comprises a vertical-cavity surface-emitting laser (VCSEL). The bandgap for the semiconductor material of each optical emitter is selected to emit electromagnetic radiation at a discrete portion of the energy spectrum. The device (D3) further comprises a waveguide for guiding electromagnetic radiation emitted by each of the several optical emitters, the optoelectronic device emitting white RGB electromagnetic radiation. Preferred Method: The method further involves epitaxially growing a second p/n junction in a CVD process in a continuous system, the first p/n junction comprising: a second n-type semiconductor material; a second a p-type semiconductor material, where each of the first doped semiconductor material and the second doped semiconductor material comprises the compound (II); epitaxially growing resonant interband tunnel diode after the epitaxial growth of the first p/n junction and before the growth of the second p/n junction; epitaxially growing a transparent electrical contact on the uppermost surface of the photodiode, the contact comprising a conducting oxides selected from indium tin oxide, zinc indium oxide, zinc tin oxide or conducting n-ZnO doped with aluminum, and/or indium, and/or gallium, by varying the composition of a vapor source of zinc, a vapor source of Al, In and/or Ga, and a vapor source of O. Preferred Definitions:    x=0.7-0.9;    y=0.8-0.9;    A'=Cd;and    B'=Te.