Effect of Buffer Thickness on the Formation of ZnO Nanorods Grown by MOCVD

2007 ◽  
Vol 124-126 ◽  
pp. 101-104
Author(s):  
Dong Chan Kim ◽  
Bo Hyun Kong ◽  
Young Yi Kim ◽  
Hyung Koun Cho ◽  
Jeong Yong Lee ◽  
...  
Keyword(s):  
Large Scale ◽  
Zno Nanorods ◽  
Wide Band ◽  
Buffer Layers ◽  
Zno Films ◽  
Wide Band Gap ◽  
Si Substrates ◽  
Potential Applications ◽  
Zno Buffer Layer ◽  
Zno Semiconductor

ZnO semiconductor has a wide band gap of 3.37 eV and a large exciton binding energy of 60 meV, and displays excellent sensing and optical properties. In particular, ZnO based 1D nanowires and nanorods have received intensive attention because of their potential applications in various fields. We grew ZnO buffer layers prior to the growth of ZnO nanorods for the fabrication of the vertically well-aligned ZnO nanorods without any catalysts. The ZnO nanorods were grown on Si (111) substrates by vertical MOCVD. The ZnO buffer layers were grown with various thicknesses at 400 °C and their effect on the formation of ZnO nanorods at 300 °C was evaluated by FESEM, XRD, and PL. The synthesized ZnO nanorods on the ZnO film show a high quality, a large-scale uniformity, and a vertical alignment along the [0001]ZnO compared to those on the Si substrates showing the randomly inclined ZnO nanorods. For sample using ZnO buffer layer, 1D ZnO nanorods with diameters of 150-200 nm were successively fabricated at very low growth temperature, while for sample without ZnO buffer the ZnO films with rough surface were grown.

Effects of the Sputtering Time of AlN Buffer Layer on the Quality of ZnO Thin Films

2014 ◽  
Vol 881-883 ◽  
pp. 1117-1121 ◽  
Author(s):  
Xiang Min Zhao
Keyword(s):  
Thin Films ◽  
Buffer Layer ◽  
Rf Magnetron Sputtering ◽  
Buffer Layers ◽  
Zno Thin Films ◽  
Zno Films ◽  
Si Substrates ◽  
Atomic Force ◽  
Structure Morphology ◽  
Aln Buffer

ZnO thin films with different thickness (the sputtering time of AlN buffer layers was 0 min, 30 min,60 min, and 90 min, respectively) were prepared on Si substrates using radio frequency (RF) magnetron sputtering system.X-ray diffraction (XRD), atomic force microscope (AFM), Hall measurements setup (Hall) were used to analyze the structure, morphology and electrical properties of ZnO films.The results show that growth are still preferred (002) orientation of ZnO thin films with different sputtering time of AlN buffer layer,and for the better growth of ZnO films, the optimal sputtering time is 60 min.

Wide Band Gap Al and In Co-doped ZnO Films for Near-Infrared Plasmonic Application

Plasmonics ◽  
2021 ◽  
Author(s):  
Soumya Kannoth ◽  
Packia Selvam Irulappan ◽  
Sandip Dhara ◽  
Sankara Narayanan Potty
Keyword(s):  
Band Gap ◽  
Near Infrared ◽  
Wide Band ◽  
Zno Films ◽  
Wide Band Gap ◽  
Doped Zno ◽  
Co Doped

Epitaxial Growth of Aluminum Nitride on Sapphire and Silicon

1994 ◽  
Vol 358 ◽  
Author(s):  
K. Dovidenko ◽  
S. Oktyabrsky ◽  
J. Narayan ◽  
M. Razeghi
Keyword(s):  
Epitaxial Growth ◽  
Substrate Surface ◽  
Wide Band ◽  
X Ray Diffraction ◽  
Wide Band Gap ◽  
High Quality ◽  
Microstructural Characteristics ◽  
X Ray ◽  
Si Substrates ◽  
Transmission Electron

ABSTRACTThe microstructural characteristics of wide band gap semiconductor, hexagonal A1N thin films on Si(100), (111), and sapphire (0001) and (10ī2) were studied by transmission electron microscopy (TEM) and x-ray diffraction. The films were grown by MOCVD from TMA1 + NH3 + N2 gas mixtures. Different degrees of film crystallinity were observed for films grown on α-A12O3 and Si substrates in different orientations. The epitaxial growth of high quality single crystalline A1N film on (0001) α-Al2O3 was demonstrated with a dislocation density of about 2*10 10cm−2 . The films on Si(111) and Si(100) substrates were textured with the c-axis of A1N being perpendicular to the substrate surface.

First Principles Modelling of Scroll-to-Nanotube Defect: Screw-Type Dislocation

2006 ◽  
Vol 527-529 ◽  
pp. 1583-1586 ◽  
Author(s):  
I. Suarez-Martinez ◽  
G. Savini ◽  
M.I. Heggie
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Wide Band ◽  
Interlayer Spacing ◽  
Density Functional Theory Study ◽  
Wide Band Gap ◽  
Functional Theory ◽  
Potential Applications ◽  
Wide Band Gap Semiconductors ◽  
Type Dislocation

Carbon nanotubes present interesting potential applications especially in nanoelectronics. Their electrical properties are known to be a function of their chirality. It happens that 1/3 of CNs are metallic and 2/3 are semiconductors. Narrow nanotubes are expected to be wide-band gap semiconductors. Several experimental results have shown that the thickness of a multi-wall nanotube along the axis can change, while the interlayer spacing remains fairly constant. These observations suggest the coexistence in the same tube of a scroll structure and a multi-wall nested tube. We explain this defect as a screw dislocation which by gliding transforms between these two forms. In this paper, we present a density functional theory study of the structure and energetics of screw dislocations in AA and ABC graphite, and we discuss their role in the scroll-to-nanotube transformation in multi-wall nanotubes.

Structural and Electrical Properties of Hydrothermal Growth ZnO Nanorods

2015 ◽  
Vol 1109 ◽  
pp. 104-107
Author(s):  
K.L. Foo ◽  
U. Hashim ◽  
Chun Hong Voon ◽  
M. Kashif
Keyword(s):  
Electrical Properties ◽  
Zno Nanorods ◽  
Wide Band ◽  
Hydrothermal Growth ◽  
Oxide Semiconductor ◽  
Wide Band Gap ◽  
Interdigitated Electrode ◽  
Growth Technique ◽  
Xrd Pattern ◽  
Structural And Electrical Properties

ZnO nanorods, type of the metal-oxide semiconductor deposited on interdigitated electrode (IDE) substrate using hydrothermal growth technique. The growth ZnO nanorods was annealed in furnace at 500°C for 2 hours as to obtain highly crystallite of ZnO nanorods. XRD pattern indicated the synthesized ZnO nanorods have preferred orientation along the (002) plane. Moreover, FESEM images showed that the nanorods with the size less than 60 nanometer were successfully synthesized using hydrothermal growth technique. The investigation on optical properties using UV-Vis-NIR spectrophotometer confirmed ZnO is classified as a wide band gap semiconductor material. Furthermore, the growth ZnO nanorods which undergo electrical properties testing using dielectric analyzer and source meter show that the ZnO nanorods demonstrated rectifying behaviour.

Characterization of Gan/Sapphire Interface and the Buffer Layer by TEM/AFM

2001 ◽  
Vol 7 (S2) ◽  
pp. 330-331
Author(s):  
B. Shea ◽  
Q. Sun-Paduano ◽  
D. F. Bliss ◽  
M. C. Callahan ◽  
C. Sung
Keyword(s):  
Buffer Layer ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Wide Band ◽  
Buffer Layers ◽  
Organic Chemical ◽  
Wide Band Gap ◽  
Tem Analysis ◽  
Flow Rates ◽  
Device Applications

Interest in wide band gap III-V nitride semiconductor devices is increasing for optoelectronic and microelectronic device applications. to ensure the highest quality, TEM analysis can characterize the substrate and buffer layer interface. Measurements taken by TEM reveal the density of dislocations/cm2 and the orientation of Burger's vectors. This information allows for changes to be made in deposition rates, temperatures, gas flow rates, and other parameters during the processing.The GaN/sapphire samples grown at AFRL were produced in two consecutive steps, first to provide a thin buffer layer, and the other to grow a lum thick epitaxial film. Both growth steps were prepared using metallic organic chemical vapor deposition (MOCVD) in a vertical reactor. Buffer layers were prepared using a range of temperatures from 525 to 535°C and with a range of flow rates and pressures in order to optimize the nucleation conditions for the epitaxial films.

Epitaxial ZnO films on (111) Si substrates with Sc2O3 buffer layers

2009 ◽  
Vol 94 (12) ◽  
pp. 122107 ◽  
Author(s):  
W. Guo ◽  
M. B. Katz ◽  
C. T. Nelson ◽  
T. Heeg ◽  
D. G. Schlom ◽  
...  
Keyword(s):  
Buffer Layers ◽  
Zno Films ◽  
Si Substrates

EPR Study of the Role of Hydrogen in the Defect Formation Upon Heat Treatment of Oxidized SiC

1998 ◽  
Vol 513 ◽  
Author(s):  
P. J. Macfarlane ◽  
M. E. Zvanut
Keyword(s):  
Heat Treatment ◽  
Defect Formation ◽  
Wide Band ◽  
Oxide Semiconductor ◽  
Wide Band Gap ◽  
Paramagnetic Resonance ◽  
Hydrogen Incorporation ◽  
Si Substrates ◽  
Mos Devices ◽  
Dry Heat Treatment

ABSTRACTFor the past several years hydrogen incorporation in metal oxide semiconductor (MOS) devices has been of interest because studies have shown that vacuum annealing of oxidized Si substrates desorbs hydrogen, revealing interfacial defects. Today, in applications that require higher power and/or temperature, Si will likely be replaced with a wide-band-gap semiconductor. For MOS devices, SiC is a leading contender because it can be thermally oxidized to form a SiO2 insulating layer similar to Si. However, the SiC/SiO2 structure potentially contains hydrogen sensitive centers similar to those found in Si/SiO2 structures. Using electron paramagnetic resonance (EPR), we have observed a center 1.8 G wide peak-to-peak at g=2.0026. The center is generated in oxidized SiC that has received a 900° C dry, N2 or O2, post oxidation heat-treatment in which moisture is measured to be less than 1 ppm. Annealing at 900° C in standard Ar containing at least 50 ppm H2O decreases the center's concentration by two orders of magnitude. By comparing results from our study to studies of Si-H and C-H bonds in a-SiC:H [1] and SiC converted graphite [2], we suggest that this center is related to carbon dangling bonds created by the effusion of hydrogen during the dry heat-treatment. We will compare the activation energy for the hydrogen depassivation of our center with that found for other C-H and Si-H systems.

scholarly journals Sprayed Pyrolyzed ZnO Films with Nanoflake and Nanorod Morphologies and Their Photocatalytic Activity

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Nora S. Portillo-Vélez ◽  
Monserrat Bizarro
Keyword(s):  
Photocatalytic Activity ◽  
Large Scale ◽  
Spray Pyrolysis Technique ◽  
Structural Characteristics ◽  
Zno Nanorods ◽  
Volume Ratio ◽  
Precursor Solution ◽  
Synthesis Process ◽  
Zno Films ◽  
Scale Production

There is an increasing interest on the application of ZnO nanorods in photocatalysis and many growth methods have been applied, in particular the spray pyrolysis technique which is attractive for large scale production. However it is interesting to know if the nanorod morphology is the best considering its photocatalytic activity, stability, and cost effectiveness compared to a nonoriented growth. In this work we present a systematic study of the effect of the precursor solution (type of salt, solvent, and concentration) on the morphology of sprayed ZnO films to obtain nanoflakes and nanorods without the use of surfactants or catalysts. The surface properties and structural characteristics of these types of films were investigated to elucidate which morphology is more favorable for photocatalytic applications. Wettability and photocatalytic experiments were carried out in the same conditions. After UV irradiation both morphologies became hydrophilic and achieved a dye discoloration efficiency higher than 90%; however, the nanoflake morphology provided the highest photocatalytic performance (99% dye discoloration) and stability and the lowest energy consumption during the synthesis process. The surface-to-volume ratio revealed that the nanoflake morphology is more adequate for photocatalytic water treatment applications and that the thin nanorods should be preferred over the large ones.

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