The photoluminescence, field emission and femtosecond nonlinear absorption properties of Al-doped ZnO nanowires, nanobelts, and nanoplane-cone morphologies

Abstract

Al-doped ZnO (AZO) nanowires, nanobelts and nanoplane-cone nanostructures have been successfully synthesized. The structural, photoluminescence (PL) and field emission (FE) properties of AZO nanowires have been characterized. The dependence of the PL properties of AZO nanostructures versus excitation laser power in the range from 1 to 12 mW and temperature in the range of 10-273 K was discussed. The PL measurement results demonstrated that the ultraviolet emission came from a near band edge emission, and two peaks in visible light region were due to deep-level emission. Moreover, the AZO nanowires have a relatively stronger ultraviolet emission than other kinds of samples. The FE measurements indicate that the turn-on field for the nanoplane-cone structure is 2.52 V μm-1, which is smaller than 4.42 V μm-1 for nanowires and 5.28 V μm-1 for nanobelts. In addition, the nonlinear absorption properties of AZO nanowires were measured using a femtosecond Z-scan technique. The effect of morphology on the nonlinear optical absorption properties of AZO nanowires was studied. From the results, the AZO nanowires show reverse saturable absorption (RSA) behavior. Furthermore, the results show that the order of magnitude of the nonlinear absorption coefficient for AZO nanowires is ∼10-2 cm3 GW-2. Our results show that AZO films are a promising candidate in further optoelectronic device applications.