Na doping concentration tuned conductivity of ZnO films via pulsed laser deposition and electroluminescence from ZnO homojunction on silicon substrate

The conduction types of Na-doped ZnO films with different Na contents were investigated by repeated Hall-effect measurements and rectification behaviour of ZnO : Al/ZnO : Na homojunctions. A p-type ZnO : Na film with a resistivity of 13.8-19 Omega cm, Hall mobility of 0.12-1.42 cm(2) V-1 s(-1) and hole concentration of 4.78 x 10(17)-4.66 x 10(18) cm(-3) was achieved, and it was electrically stable over 9 months. The effect of the Na concentration on the conductivity of ZnO films was discussed tentatively from the results of x-ray diffraction and Hall-effect measurements as well as from the viewpoint of Madelung energy. Electroluminescence was obtained at 160K from the optimized p-n homojunction on the silicon substrate.