Fabrication of wide-band-gap MgxZn1-xO quasi-ternary alloys by molecular-beam epitaxy -: art. no. 192911

A series of wurtzite MgZnO quasi-ternary alloys, which consist of wurtzite MgO/ZnO superlattices, were grown by molecular-beam epitaxy on sapphire substrates. By changing the thicknesses of ZnO layers and/or of MgO layers of the superlattice, the band-gap energy was artificially tuned from 3.30 to 4.65 eV. The highest band gap, consequently realized by the quasi-ternary alloy, was larger than that of the single MgZnO layer, we have ever reported, keeping the wurtzite structure. The band gap of quasi-ternary alloys was well analyzed by the Kronig- Penny model supposing the effective masses of wurtzite MgO as 0.30m(0) and (1 - 2)m(0) for electrons and holes, respectively. (c) 2005 American Institute of Physics.