Structural Analysis of ZnO Nanorods Grown on a ZnO Homo-Buer Layer by Using MOCVD

S.-W. Han 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.1

Vertically well-aligned ZnO nanorods were fabricated on Al2O3 with ZnO homo-buer layers or GaN interlayers by using a catalyst-free metal-organic chemical vapor deposition (MOCVD). X-ray diraction (XRD) measurements demonstrated that, compared with the nanorods grown on the GaN interlayer, a substantial amount of structural disorders existed in the ZnO nanorods grown on the ZnO homo-buer layer. Field-emission transmission electron microscope (FE-TEM) measurements from the interfaces of the nanorods and the substrates also exhibited structural disorders existing in the bottom part of the ZnO nanorods grown on the sapphire and on the ZnO homo-buer layer while no distinguishable disorder was observed at the ZnO/GaN interface. However, extended X-ray absorption ne structure measurements at the Zn K edge revealed that a small, but distinguishable, amount of structural disorder existed in the Zn-O pairs in the beginning of the nanorod growth. Our observation strongly suggests that structural strain due to the surface roughness of the ZnO homo-buer layer and to the lattice mismatch between the ZnO and the GaN mainly contributed to island growth in the beginning of the ZnO nanorod growth. Vertically well-aligned ZnO nanorods were fabricated on Al2O3 with ZnO homo-buer layers or GaN interlayers by using a catalyst-free metal-organic chemical vapor deposition (MOCVD). X-ray diraction (XRD) measurements demonstrated that, compared with the nanorods grown on the GaN interlayer, a substantial amount of structural disorders existed in the ZnO nanorods grown on the ZnO homo-buer layer. Field-emission transmission electron microscope (FE-TEM) measurements from the interfaces of the nanorods and the substrates also exhibited structural disorders existing in the bottom part of the ZnO nanorods grown on the sapphire and on the ZnO homo-buer layer while no distinguishable disorder was observed at the ZnO/GaN interface. However, extended X-ray absorption ne structure measurements at the Zn K edge revealed that a small, but distinguishable, amount of structural disorder existed in the Zn-O pairs in the beginning of the nanorod growth. Our observation strongly suggests that structural strain due to the surface roughness of the ZnO homo-buer layer and to the lattice mismatch between the ZnO and the GaN mainly contributed to island growth in the beginning of the ZnO nanorod growth.

Growth of nanostructured ZnO on wearable fabrics for functional garment

Park, Hyejin,Tong, Fei,Sujan, Achintya,Chung, Yoonsung,Park, Minseo,Tatarchuk, Bruce J.,Koo, Helen,Ahn, Hosang,Yoon, Young Soo,Kim, Dong-Joo Elsevier 2014 Materials letters Vol.118 No.-

<P><B>Abstract</B></P> <P>ZnO thin films and nanorods were grown via a wet chemical route on various wearable fabrics such as cotton, nylon, and polyester. The seed layer of ZnO was deposited by a dip-pad-cure method, and thermolysis assisted chemical solution method was used to grow well-aligned ZnO nanorods. The growth behaviors were investigated by comparing ZnO nanorods with/without a seed layer and on different fabrics. The seed layer significantly influenced the growth of ZnO nanorods while the types of fabrics did not. Nanostructured ZnO on fabrics showed reduced diffused reflectance near 380nm by absorbing UV light. Increased electrical conductivity was also observed due to the ZnO nanorods.</P> <P><B>Highlights</B></P> <P> <UL> <LI> ZnO nanostructures were grown at low temperature via solution methods on fabrics. </LI> <LI> The ZnO seed layer was critical for the growth of ZnO nanorods on fabrics. </LI> <LI> The ZnO nanorods on fabrics showed comparable properties with solid substrates. </LI> </UL> </P>

A facile route to ionic liquids-functionalized ZnO nanorods for the fluorometric sensing of thiabendazole drug

Kaur, Narinder,Raj, Pushap,Singh, Amanpreet,Singh, Narinder,Kim, Deuk Young Elsevier 2018 Journal of molecular liquids Vol.261 No.-

<P>In this report, we introduce a simple and cost-effective hydrothermal method for the functionalization of ZnO nanorods with three different ionic liquids (ILs (1-3)) to check their sensing response with various drugs including thiabendazole, phenylbutazone, chloramphenicol, neomycin, and theophylline through fluorescence spectroscopy. The rod like-microstructure and hexagonal wurtzite structure of synthesized ZnO nanorods were examined with SEM-EDS and XRD techniques. On the other hand, ionic liquids-functionalized ZnO nanorods (ILs (1-3)/ZnO) exhibited various self-organized (layered-sheet similar to IL1, distorted nanorods similar to IL2, peanut beaded surface similar to IL3/ZnO) structures due to the intercalation of ILs on the surface of ZnO nanorods. Compared to ZnO nanorods, similar to ILs (1-3)/ZnO nanorods showed a blue shift in UV-absorption band which resulted to the variation in optical bandgap values. Ionic liquids-functionalized nanorods samples (ILs (1-3)/ZnO) have been selected for their recognition behaviour with available drug molecules using fluorescence spectroscopic technique. Interestingly, with the addition of thiabendazole drug molecules to two samples (ILs (1,3)/ZnO), a significant response corresponding to the peaks at similar to 350 nm and similar to 357 nm was observed, which led to the development of fluorescent sensors with a detection limit of 12 and 304 nM, respectively. (C) 2018 Elsevier B.V. All rights reserved.</P>

Nonlinear Optical Properties of ZnO Nanorods Prepared by Using the Electro-deposition Method

Soon-Ki Min,오차환,Geon Joon Lee,이영백,민선기,한성환 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.3

We studied the nonlinear optical properties of ZnO nanorods. ZnO nanorods were deposited by using the electro-deposition method, and these samples were annealed at a temperature of 400 ˚C for 5 hours. The nonlinear absorption properties of ZnO nanorods with two different rod diameters of 500 nm and 100 nm were measured by using the femtosecond nonlinear transmission method at an incident wavelength of 800 nm. The nonlinear absorption coefficients of ZnO nanorods were 5.9 × 10−7 cm/W and 2.3 × 10−7 cm/W for rod diameters of 500 nm and 100 nm, respectively, and these nonlinear absorption coefficients were about 100 times larger than those already reported for ZnO thin films. The enhanced nonlinear absorption in ZnO nanorods was due to the combination of the two-photon absorption and optical confinement. We studied the nonlinear optical properties of ZnO nanorods. ZnO nanorods were deposited by using the electro-deposition method, and these samples were annealed at a temperature of 400 ˚C for 5 hours. The nonlinear absorption properties of ZnO nanorods with two different rod diameters of 500 nm and 100 nm were measured by using the femtosecond nonlinear transmission method at an incident wavelength of 800 nm. The nonlinear absorption coefficients of ZnO nanorods were 5.9 × 10−7 cm/W and 2.3 × 10−7 cm/W for rod diameters of 500 nm and 100 nm, respectively, and these nonlinear absorption coefficients were about 100 times larger than those already reported for ZnO thin films. The enhanced nonlinear absorption in ZnO nanorods was due to the combination of the two-photon absorption and optical confinement.

Structural and optical properties of ZnO nanorods dependence on the molar ratio of zinc acetate dihydrate to hexamethylenetetramine

Chang Chun Chen,Nan Ye,ChuanFu YU,Ting FAN 한양대학교 세라믹연구소 2014 Journal of Ceramic Processing Research Vol.15 No.2

ZnO nanorods were grown on glass substrates coated by an Al-doped ZnO seed layer via a simple solvothermal method using zinc acetate dihydrate (Zn(CH3COO)2 • 2H2O) and Hexamethylenetetramine (C6H12N4) reagent. The structure, morphology and optical properties of these ZnO nanorods dependence on the molar ratio of Zn(CH3COO)2 • 2H2O to C6H12N4 were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Ultraviolet and Visible Spectrophotometry (UV-vis) and photoluminescence (PL) spectrometry, respectively. The XRD patterns indicated that all the ZnO nanorods were well-faceted hexagonal structures and preferentially grown along the c-axis. As the molar ratio of Zn(CH3COO)2 • 2H2O to C6H12N4 decreasing from 2.5 to 0.25, the crystallinity of ZnO nanorods synthesized gradually became inferior and the width of ZnO nanorods also decreased. The blue-shifts of UV emission excited from ZnO nanorods probably arised from the decreased size of ZnO nanorods.

수열합성법을 이용한 ZnO 나노 막대의 선택 성장 연구

김아라,장판,김창회,김홍승 한국물리학회 2012 새물리 Vol.62 No.8

We have investigated the effects of surface pattern size on the characteristics of hydrothermally grown ZnO nanorods. The sputtered ZnO seed layer on a Si substrate was patterned with features of various sizes by using nano-imprint technology for the selective growth of ZnO nanorods. The diameters and the lengths of the ZnO nanorods depended on the pattern feature size within several micrometers. The ZnO nanorods grown on small-pattern regions had large diameters and small lengths relative to those grown on large-pattern regions. The observation in this study suggests that controlling the pattern size of the ZnO seed layer on a substrate can control the morphology of the ZnO nanorod array. 본 연구에서는 수열합성법을 이용하여 패턴 영역의 크기에 대한 산화아연(ZnO, zinc oxide) 나노 막대 성장을 살펴보았다. ZnO와 Si기판의 격자상수 차이를 이용하여 ZnO 나노 막대를 선택적 영역에 성장시키고자스퍼터링 시스템으로 증착된 ZnO 씨앗층을 원하는 크기와 모양으로패턴화 하고자 하였으며 사용된 노광 기법은 광원의 파장에 제약을 받지않고 비교적 나노 스케일의 패턴을 재현성 있게 제작 가능한나노임프린트 공정을 이용하였다. ZnO 나노 막대는 패턴된 ZnO 씨앗층영역에 선택적으로 성장하였으며, ZnO 나노 막대의 직경과 길이의 크기는패턴된 ZnO 씨앗층의 수 μm크기의 변화에 따라 큰 영향을 받아 패턴크기가 작아질수록 큰 직경과 짧은 길이를 가지는 ZnO 나노 막대가 성장되었다.

CBD 방법에 의해 제조된 ZnO 나노로드의 전기적 특성

김진호,이미재,황종희,임태영,Kim, Jin-Ho,Lee, Mi-Jai,Hwang, Jonghee,Lim, Tae-Young 한국재료학회 2012 한국재료학회지 Vol.22 No.12

ZnO nanorods were successfully fabricated on Zn foil by chemical bath deposition (CBD) method. The ZnO precursor concentration and immersion time affected the surface morphologies, structure, and electrical properties of the ZnO nanorods. As the precursor concentration increased, the diameter of the ZnO nanorods increased from ca. 50 nm to ca. 150 nm. The thicknesses of the ZnO nanorods were from ca. $1.98{\mu}m$ to ca. $2.08{\mu}m$. ZnO crystalline phases of (100), (002), and (101) planes of hexagonal wurtzite structure were confirmed by XRD measurement. The fabricated ZnO nanorods showed a photoluminescene property at 380 nm. Especially, the ZnO nanorods deposited for 6 h in solution with a concentration of 0.005M showed a stronger (101) peak than they did (100) or (002) peaks. In addition, these ZnO nanorods showed a good electrical property, with the lowest resistance among the four samples, because the nanorods were densely in contact and relatively without pores. Therefore, a ZnO nanorod substrate is useful as a highly sensitive biochip substrate to detect biomolecules using an electrochemical method.

ZnO:Al 시드 막의 보론 농도가 ZnO 나노로드의 성장 및 특성에 미치는 영향

마대영(Tae-Young Ma),박기철(Ki-Cheol Park) 대한전기학회 2017 전기학회논문지 Vol.66 No.10

Boron-doped ZnO:Al films were deposited by rf magnetron sputtering. The structural and optical property variations of the films with the boron amounts were studied. ZnO nanorods were grown on SiO2/Si wafers and glass by a hydrothermal method. ~50 nm-thick boron-doped ZnO:Al films were deposited on the substrates as seed layers. The mixed solution of zinc nitrate hexahydrate and hexamethylenetetramine in DI water was used as a precursor for ZnO nanorods. The concentration of zinc nitrate hexahydrate and that of hexamethylenetetramine were 0.05 mol, respectively. ZnO nanorods were grown at 90 °C for 2 hours. X-ray diffraction was conducted to observe the crystallinity of ZnO nanorods. A field emission scanning electron microscope was employed to study the morphology of nanorods. Optical transmittance was measured by a UV-Vis spectrophotometer, and photoluminescence was carried out with 266 nm light. The ZnO nanorods grown on the 0.5 wt% boron-doped ZnO seed layer showed the best crystallinity.

Photocurrent detection of chemically tuned hierarchical ZnO nanostructures grown on seed layers formed by atomic layer deposition

Bang, Seokhwan,Lee, Seungjun,Ko, Youngbin,Park, Joohyun,Shin, Seokyoon,Seo, Hyungtak,Jeon, Hyeongtag Springer 2012 NANOSCALE RESEARCH LETTERS Vol.7 No.1

<P>We demonstrate the morphological control method of ZnO nanostructures by atomic layer deposition (ALD) on an Al<SUB>2</SUB>O<SUB>3</SUB>/ZnO seed layer surface and the application of a hierarchical ZnO nanostructure for a photodetector. Two layers of ZnO and Al<SUB>2</SUB>O<SUB>3</SUB> prepared using ALD with different pH values in solution coexisted on the alloy film surface, leading to deactivation of the surface hydroxyl groups. This surface complex decreased the ZnO nucleation on the seed layer surface, and thereby effectively screened the inherent surface polarity of ZnO. As a result, a 2-D zinc hydroxyl compound nanosheet was produced. With increasing ALD cycles of ZnO in the seed layer, the nanostructure morphology changes from 2-D nanosheet to 1-D nanorod due to the recovery of the natural crystallinity and polarity of ZnO. The thin ALD ZnO seed layer conformally covers the complex nanosheet structure to produce a nanorod, then a 3-D, hierarchical ZnO nanostructure was synthesized using a combined hydrothermal and ALD method. During the deposition of the ALD ZnO seed layer, the zinc hydroxyl compound nanosheets underwent a self-annealing process at 150 °C, resulting in structural transformation to pure ZnO 3-D nanosheets without collapse of the intrinsic morphology. The investigation on band electronic properties of ZnO 2-D nanosheet and 3-D hierarchical structure revealed noticeable variations depending on the richness of Zn-OH in each morphology. The improved visible and ultraviolet photocurrent characteristics of a photodetector with the active region using 3-D hierarchical structure against those of 2-D nanosheet structure were achieved.</P>

Improved Ultraviolet Photoresponse Properties of ZnO Nanorods Grown by Using Hydrothermal Method Applied Rotating Precursor Solution

김동완,임재영 대한금속·재료학회 2021 대한금속·재료학회지 Vol.59 No.3

We grew ZnO nanorods (NRs) using a hydrothermal method while rotating the precursor solution, and report the effect of rotation on surface modification, and the optical and ultraviolet (UV) photoresponse properties of the resulting ZnO nanorods. The ZnO NRs grown in the rotating precursor solution at 100 rpm had the longest length and diameter, which decreased with increasing rotation rate above 100 rpm. Also, the intensity of the diffraction peaks from ZnO (002) and (100) was strongest and weakest for the ZnO NRs grown in a rotating solution at 150 rpm, respectively, indicating improvement in the c-axis orientation of the ZnO NRs. In the PL spectra, near-band-edge (NBE) and deep-level (DL) emissions were observed from all of the ZnO NRs. The intensity of the NBE emission gradually increased with increasing rotation rate, due to the increase in surface area. Also, the intensity of the DL emission gradually increased with increasing rotation rate because of the increasing number of interstitial oxygens. Analysis of the UV photoresponse found the photocurrent of the ZnO NRs grown in the rotating precursor solution was higher than that of ZnO NRs grown in a non-rotated precursor solution. In particular, ZnO NRs grown in a rotating precursor solution at 150 rpm exhibited the highest value of photosensitivity, with high reproducibility.