Rational synthesis and tunable optical properties of quasialigned Zn1−xMgxO nanorods

Quasialigned, single-crystal Zn1−xMgxO (x=0–0.32) nanorods were synthesized on Si substrates by thermal evaporation. Zn1−xMgxO nanorods grew along the [0001] crystal direction and had uniform hexagonal planes with diameters of 420–120nm. The predominant ultraviolet luminescence could be tuned from 379 (x=0) to 305nm (x=0.32) at room temperature. This blueshift indicated the band gap engineering in Zn1−xMgxO nanorods. Temperature-dependent photoluminescence was used to illustrate the free-exciton emission from Zn1−xMgxO nanorods. The exciton binding energy decreased from 59 (x=0) to 49meV (x=0.18) and then increased to 54meV (x=0.32).