$MgxZn1−xO$ as a II–VI widegap semiconductor alloy

We propose a widegap II–VI semiconductor alloy, $MgxZn1−xO,$ for the fabrication of heteroepitaxial ultraviolet light emitting devices based on ZnO. The $c$-axis oriented $MgxZn1−xO$ films were epitaxially grown by pulsed laser deposition on ZnO epitaxial films and sapphire (0001) substrates using ceramic targets. Solid solution films were prepared with Mg content up to $x=0.33,$ achieving a band gap of 3.99 eV at room temperature. MgO impurity phase segregated at $x⩾0.36.$ Lattice constants of $MgxZn1−xO$ films changed slightly $(∼1%),$ increasing in $a$ axis and decreasing in $c$-axis direction with increasing $x.$ These films showed ultraviolet photoluminescence at energies from 3.36 $(x=0)$ to 3.87 eV $(x=0.33)$ at 4.2 K.