MGXZN1-XO AS A II-VI WIDEGAP SEMICONDUCTOR ALLOY

We propose a widegap II-VI semiconductor alloy, MgxZn1-xO, for the fab rication of heteroepitaxial ultraviolet light emitting devices based o n ZnO. The c-axis oriented MgxZn1-xO films were epitaxially grown by p ulsed laser deposition on ZnO epitaxial films and sapphire (0001) subs trates using ceramic targets. Solid solution films were prepared with Me content up to x=0.33, achieving a band gap of 3.99 eV at room tempe rature. MgO impurity phase segregated at x greater than or equal to 0. 36. Lattice constants of MgxZn1-xO films changed slightly (similar to 1%), increasing ina axis and decreasing in c-axis direction with incre asing x. These films showed ultraviolet photoluminescence at energies from 3.36 (x=0) to 3.87 eV (x=0.33) at 4.2 K. (C) 1998 American Instit ute of Physics. [S0003-6951(98)04219-3].