Study Of Optical Properties In Al/Ga Codoped ZnO Nano-arrays

Semiconductor nanomaterials are ideal materials for the application of optoelectronic devices integration and miniaturization, which have unique properties, such as quantum size effect, volume effect, surface effect, the macroscopic quantum tunnel effect and dielectric limit domain effect and so on. Zinc oxide(Zn O) is one kind of typical transparent semiconductor, with wide band gap of 3.37 e V. Zn O has important application values in optoelectronic devices because of the rich resources, non-toxic. And doped Zn O nanomaterials have attained much attention for the surface plasmonic resonant absorption peaks in infrared(IR) region, which can be tuned like in noble metallic nanomaterials. In this paper, the linear and third-order nonlinear optical properties in Al/Ga co-doped Zn O nano-triangle arrays were investigated. The main contents are as follows:(1) AGZO nano-triangle arrays with different sizes and different doping concentrations were prepared on quartz substrate by the methods of nanosphere lithography and pulse laser deposition. The surface morphology of the AGZO nano-triangle arrays were measured by scanning electron microscopy and atomic force microscopy. The results show that the AGZO nano-triangle arrays were uniformly distributed.(2) Optical transmission spectra in the UV-visible range(from 190 nm to 900nm) of AGZO nano-triangle arrays and films with different doping concentration were performed by UV-visible spectrophotometer. The transmission spectra in the infrared range were measured by Fourier transform infrared(FTIR) spectrometer. The results show that the surface plasmonic resonant absorption peaks shift to short wavelengths with increasing of Al doping concentration.(3) The third-order nonlinear optical properties in the AGZO nano-triangle arrays were investigated by Z-scan method, excited by femtosecond laser(800 nm, 40 fs). The results show that the AGZO nano-triangle arrays have the enhanced third-order nonlinear refractive indexes up to 3.4 folds of the films. The local field enhancement effect in the nano-triangle arrays were analyzed by finite difference time domain simulation. And the influences of the Al doping concentration on the third-order nonlinearities of the AGZO nano-triangle arrays were studied. The results indicate AGZO nano-triangle arrays have potential applications for nonlinear optical devices like all-optical switching, optical limiting and other types of signal processing.