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Diameter Control and Photoluminescence of ZnO Nanorods from Trialkylamines  [PDF]
Tamar Andelman,Yinyan Gong,Gertrude Neumark,Stephen O'Brien
Journal of Nanomaterials , 2007, DOI: 10.1155/2007/73824
Abstract: A novel solution method to control the diameter of ZnO nanorods is reported. Small diameter (2-3 nm) nanorods were synthesized from trihexylamine, and large diameter (50–80 nm) nanorods were synthesized by increasing the alkyl chain length to tridodecylamine. The defect (green) emission of the photoluminescence (PL) spectra of the nanorods varies with diameter, and can thus be controlled by the diameter control. The small ZnO nanorods have strong green emission, while the large diameter nanorods exhibit a remarkably suppressed green band. We show that this observation supports surface oxygen vacancies as the defect that gives rise to the green emission.
Fabrication and Photoluminescence Properties of ZnO Nanorods
ZHONG Hong-Mei,LU Wei,SUN Yan,LI Zhi-Feng,

中国物理快报 , 2007,
Abstract: ZnO nanorods are successfully synthesized by annealing the precursors in argon with the chemical precipitation method. The structural and optical properties of ZnO nanorods are investigated. As annealing temperature increases, the intensity of the green emission increases while the intensity of the yellow emission decreases. The result suggests that the green emission depends strongly on the annealing temperature.
Photoluminescence of spray pyrolysis deposited ZnO nanorods  [cached]
K?rber Erki,Raadik Taavi,Dedova Tatjana,Krustok Jüri
Nanoscale Research Letters , 2011,
Abstract: Photoluminescence of highly structured ZnO layers comprising well-shaped hexagonal rods is presented. The ZnO rods (length 500-1,000 nm, diameter 100-300 nm) were grown in air onto a preheated soda-lime glass (SGL) or ITO/SGL substrate by low-cost chemical spray pyrolysis method using zinc chloride precursor solutions and growth temperatures in the range of 450-550°C. We report the effect of the variation in deposition parameters (substrate type, growth temperature, spray rate, solvent type) on the photoluminescence properties of the spray-deposited ZnO nanorods. A dominant near band edge (NBE) emission is observed at 300 K and at 10 K. High-resolution photoluminescence measurements at 10 K reveal fine structure of the NBE band with the dominant peaks related to the bound exciton transitions. It is found that all studied technological parameters affect the excitonic photoluminescence in ZnO nanorods. PACS: 78.55.Et, 81.15.Rs, 61.46.Km
Photoluminescence Properties of ZnO Nanorods Prepared Under Low Temperature

Lang Jihui,Yang Jinghai,Li Changsheng,Han Qiang,Yang Lili,Wang Dandan,Gao Ming,Liu Xiaoyan,

半导体学报 , 2008,
Abstract: Zinc oxide (ZnO) nanorods are grown on ITO conducting glass with the chemical bath deposition (CBD) method.XRD,SEM,and PL are used to characterize the crystal structures,surface morphologies,and photoluminescence properties of ZnO nanorods.The X-ray measurement results show that the growth orientation of the as-prepared ZnO nanorods is (002).The SEM results show that the size of ZnO nanorods increases with the molar concentration of zinc nitrate,and the diameter and length of nanorods increases significantly through tuning the reaction time when the molar concentration is 0.1M.The photoluminescence measurements show that the all the samples have good photoluminescence behaviors.The crystallization of the samples increases with the molar concentration of zinc nitrate and the reaction time.
Photoluminescence and Structural Properties of ZnO Nanorods Growth by Assisted-Hydrothermal Method  [PDF]
S. López-Romero, M. García-H
World Journal of Condensed Matter Physics (WJCMP) , 2013, DOI: 10.4236/wjcmp.2013.33024

Semiconducting zinc oxide (ZnO) nanorods were obtained in bulk quantity by an hexamethylenetetramine (HMTA)-assisted hydrothermal method at low temperature (90°C) with methenamine ((CH3)6N4 as surfactant and catalyst and zinc nitrate Zn(NO3)2·6H2O as Zn source. The structure and phase of ZnO nanorods were studied using x-ray diffraction (XRD) and high resolution transmission electron microscopy techniques (HRTEM). The morphology of the nanostructures was studied by scanning electron microscope (SEM) method. The photoluminescence (PL) properties were investigated founding two emission bands under UV excitation.

Growth and Photoluminescence of ZnO and Zn1-xMgxO Nanorods by High-pressure Pusled Laser Deposition  [PDF]
ZHANG Peng, WANG Pei-Ji, CAO Bing-Qiang
无机材料学报 , 2012, DOI: 10.3724/sp.j.1077.2012.12015
Abstract: The influence of the experimental parameters such as temperature, target, and thickness of catalyst layer on the growth of nanorods were systemically studied by a newly designed and home-built high-pressure pulsed laser deposition Zn1-xMgxO (PLD). The growth mechanism and photoluminescence properties of ZnO and Zn1-xMgxO nanorods were also investigated. It was found that c-orientated ZnO nanorod arrays grown on silicon substrate were obtained when the growth temperature was 925 nd the thickness of gold catalyst layer was 2 nm. It was also proved that growth temperature and catalyst layer thickness were both crucial for the diameter and growth density of ZnO nanorods. A combination of vapor-liquid-solid (VLS) and vapor-solid (VS) mechanism was proposed to describe the growth of ZnO nanorods by high-pressure PLD. Zn1-xMgxO nanorods and nanobelts with random orientation were grown by doping the ZnO target with MgO. The bandgap of ZnO was effectively expanded together with defect-related levels formation in the forbidden gap, which also induced enhancement of visible peak emission.
Synthesis, microstructure and photoluminescence of well-aligned ZnO nanorods on Si substrate
L. Miao, Y. Ieda, S. Tanemura, Y.G. Cao, M. Tanemura, Y. Hayashi, S. Toh and K. Kaneko
Science and Technology of Advanced Materials , 2007,
Abstract: Well-aligned zinc oxide (ZnO) nanorods were densely grown on Si substrate using ZnO thin-film seed layer without any catalysts and/or additives by a simple solid–vapour phase thermal sublimation technique. The growth mechanism can be interpreted as self-catalyst of zinc particles based on vapour–solid (VS) mechanism. High-resolution transmission electron microscopy (HRTEM) image and selected area electron diffraction (SAED) pattern confirmed that the single-crystalline growth of the nanorods were preferentially along c-axis of hexagonal crystal system. High-crystal quality ZnO nanorods with strong near band edge emission centred at 380 nm can be achieved on Si substrate by the introduction of sufficient oxygen during the nanorod growth processing.
Photoluminescence transient study of surface defects in ZnO nanorods grown by chemical bath deposition  [PDF]
E. G. Barbagiovanni,V. Strano,G. Franzò,I. Crupi,S. Mirabella
Physics , 2015, DOI: 10.1063/1.4914067
Abstract: Two deep level defects (2.25 and 2.03 eV) associated with oxygen vacancies (V$_o$) were identified in ZnO nanorods (NRs) grown by low cost chemical bath deposition. A transient behaviour in the photoluminescence (PL) intensity of the two V$_o$ states was found to be sensitive to the ambient environment and to NR post-growth treatment. The largest transient was found in samples dried on a hot plate with a PL intensity decay time, in air only, of 23 and 80 s for the 2.25 and 2.03 eV peaks, respectively. Resistance measurements under UV exposure exhibited a transient behaviour in full agreement with the PL transient indicating a clear role of atmospheric O$_2$ on the surface defect states. A model for surface defect transient behaviour due to band bending with respect to the Fermi level is proposed. The results have implications for a variety of sensing and photovoltaic applications of ZnO NRs.
Effect of Dopant Concentration on Structure and Photoluminescence of ZnO:Ag Nanorods

刘奇, 王玉新, 刘子伟, 孙景昌, 张巍, 陈苗苗
Applied Physics (APP) , 2016, DOI: 10.12677/APP.2016.63005
本文利用水热生长法在掺铝氧化锌(AZO)种子层上以Ag掺杂制备出ZnO:Ag纳米棒,采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和光致发光谱(PL)对所制备样品的晶体结构、表面形貌以及光致发光性能进行了分析。结果表明,随着Ag掺杂比例的增加,ZnO:Ag纳米棒的晶格常数先增大后减小。近紫外发光峰都发生蓝移,在Zn:Ag = 1:0.03时,近紫外发光峰的强度最强,不但出现了明显的“蓝移”,而且Ag离子的掺入也使深能级发光加强。经分析得出在一定的范围内,随着Ag掺杂比例增加,ZnO:Ag纳米棒的近紫外光的强度有明显的增强。
ZnO:Ag nanorods were deposited on AZO seed layer by the hydrothermal method in different proportions of Ag doping. The structural, surface morphological and optical properties of the samples were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence (PL) spectrum. Experimental results show that the lattice constants of ZnO:Ag nanorods increase first then decrease with the rising of Ag doping concentration. And all of the NBE-peaks show blue-shift. The sample deposited at Zn:Ag = 1:0.03 has the highest NBE-peak with apparent blue-shift and a higher deep-level emission peak. So in a certain range, the NBE-peaks of ZnO:Ag nanorods increase obviously with the rising of Ag doping concentration.
Selective patterning of ZnO nanorods on silicon substrates using nanoimprint lithography  [cached]
Jung Mi-Hee,Lee Hyoyoung
Nanoscale Research Letters , 2011,
Abstract: In this research, nanoimprint lithography (NIL) was used for patterning crystalline zinc oxide (ZnO) nanorods on the silicon substrate. To fabricate nano-patterned ZnO nanorods, patterning of an n-octadecyltrichlorosilane (OTS) self-assembled monolayers (SAMs) on SiO2 substrate was prepared by the polymer mask using NI. The ZnO seed layer was selectively coated only on the hydrophilic SiO2 surface, not on the hydrophobic OTS SAMs surface. The substrate patterned with the ZnO seed layer was treated with the oxygen plasma to oxidize the silicon surface. It was found that the nucleation and initial growth of the crystalline ZnO were proceeded only on the ZnO seed layer, not on the silicon oxide surface. ZnO photoluminescence spectra showed that ZnO nanorods grown from the seed layer treated with plasma showed lower intensity than those untreated with plasma at 378 nm, but higher intensity at 605 nm. It is indicated that the seed layer treated with plasma produced ZnO nanorods that had a more oxygen vacancy than those grown from seed layer untreated with plasma. Since the oxygen vacancies on ZnO nanorods serve as strong binding sites for absorption of various organic and inorganic molecules. Consequently, a nano-patterning of the crystalline ZnO nanorods grown from the seed layer treated with plasma may give the versatile applications for the electronics devices.
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