Effect of pressure and Al doping on structural and optical properties of ZnO nanowires synthesized by chemical vapor deposition

Abstract

a b s t r a c tThe effect of Al doping concentration and oxygen ambient pressure on the structural and optical properties of chemical vapor deposition-grown, Al-doped ZnO nanowires is studied. As Al doping increases, the strength of the broad visible emission band decreases and the UV emission increases, but the growth rate depends on the oxygen pressure in a complex manner. Together, these behaviors suggest that Al doping is effective in reducing the number of oxygen vacancies responsible for visible emission, especially at low oxygen ambient pressure. The intensities and quantum efficiencies of these emission mechanisms are discussed in terms of the effect growth and doping conditions have on the underlying excitonic decay mechanisms.

Optical and Structure Analysis of ZnO:Al Film

“…Previous reports indicate that the radiative lifetime of ex-citons pure ZnO is in the nanosecond range, while in the visible range the lifetime of the emission is longer, i.e., in the range of microseconds, so this justifies the emission is stronger in the visible (Das and Mondal, 2014). However, the complex dependence of UV and visible emission intensities is still subject of controversy in the literature (Mohanta, 2014;Manzano et al, 2011;Khan et al, 2013).…”

“…Recently, ZnO spectrum was characterized by a green emission band that was associated with a defect level of oxygen vacancy (Mohanta, 2014). Also according to Wang et al (2011) ZnO displays two bands centered at 510-540 nm (green emission) and 600-640 nm (yellow emission), assigned to oxygen vacancy (V o ) and interstitial oxygen (O i ), respectively.…”

Exciton-exciton scattering in vapor phase ZnO nanoparticles

“…With passage of the excitation pulse, an additional broad band centered at about 3.22 eV is observed along with the plasma emission and is attributed to the PL emission from vapor phase ZnO nanoparticles due to excitonic recombination since it falls in the spectral region of the PL band of ZnO. 3,[17][18][19] The intensity of the plasma emission lines reduces with delay time and is suppressed after sufficient time has passed after the ablating pulse, as shown in the inset of Fig. 2.…”

“…1,2 N-type ZnO has been attracted interest as an alternative to the popular transparent conductor indium tin oxide (ITO). 3 Significant advancement is even being made to accomplish stable p-type ZnO. 4 Nanomaterials have unique physical and chemical properties, and have many different potential applications such as coatings, catalysts, sensors, magnetic data storage, solar energy devices, etc.…”

ESTUDO DOS EFEITOS DA TEMPERATURA, TEMPO DE REAÇÃO E ESTEQUIMETRIA NA SÍNTESE DE NANOBASTÕES DE ZnO PARA APLICAÇÃO EM FOTOCATÁLISE

“…Portanto, a obtenção de catalisador imobilizado, pelo seu potencial de reduzir custos de operação, é de grande interesse e vem sendo investigada. Entre as técnicas encontradas na literatura estão: crescimento na presença de templetes (Xie et al, 2012), fotolitografia (Szabó et al, 2013), eletrodeposição (Lu et al, 2014), deposição química de vapor (Mohanta et al, 2014), evaporação térmica (Li et al, 2013;Jumidali e Hashim, 2012), oxidação de lâminas de zinco em fase gasosa e aquosa (Tan et al, 2011) e rotas hidrotérmicas (Zhao et al, 2014;Ma et al, 2011).…”