ANNEALING TIME EFFECT ON NANOSTRUCTURED n-ZnO/p-Si HETEROJUNCTION PHOTODETECTOR PERFORMANCE

2015 ◽  
Vol 22 (02) ◽  
pp. 1550027 ◽  
Author(s):  
NADIR. F. HABUBI ◽  
RAID. A. ISMAIL ◽  
WALID K. HAMOUDI ◽  
HASSAM. R. ABID
Keyword(s):  
Annealing Time ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Zno Nps ◽  
Force Microscopy ◽  
Atomic Force ◽  
Junction Type ◽  
P Type ◽  
Quartz Substrates ◽  
Two Peaks

In this work, n- ZnO /p- Si heterojunction photodetectors were prepared by drop casting of ZnO nanoparticles (NPs) on single crystal p-type silicon substrates, followed by (15–60) min; step-annealing at 600∘C. Structural, electrical, and optical properties of the ZnO NPs films deposited on quartz substrates were studied as a function of annealing time. X-ray diffraction studies showed a polycrystalline, hexagonal wurtizte nanostructured ZnO with preferential orientation along the (100) plane. Atomic force microscopy measurements showed an average ZnO grain size within the range of 75.9 nm–99.9 nm with a corresponding root mean square (RMS) surface roughness between 0.51 nm–2.16 nm. Dark and under illumination current–voltage (I–V) characteristics of the n- ZnO /p- Si heterojunction photodetectors showed an improving rectification ratio and a decreasing saturation current at longer annealing time with an ideality factor of 3 obtained at 60 min annealing time. Capacitance–voltage (C–V) characteristics of heterojunctions were investigated in order to estimate the built-in-voltage and junction type. The photodetectors, fabricated at optimum annealing time, exhibited good linearity characteristics. Maximum sensitivity was obtained when ZnO / Si heterojunctions were annealed at 60 min. Two peaks of response, located at 650 nm and 850 nm, were observed with sensitivities of 0.12–0.19 A/W and 0.18–0.39 A/W, respectively. Detectivity of the photodetectors as function of annealing time was estimated.

scholarly journals UV Sensitivity of Indium-Zinc Oxide Nanofibers

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Nadezhda Markova ◽  
Olga Berezina ◽  
Nikolay Avdeev ◽  
Alexander Pergament
Keyword(s):  
Zinc Oxide ◽  
Indium Content ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Indium Zinc Oxide ◽  
Electrospinning Method ◽  
Recovery Times ◽  
Response And Recovery

Indium-zinc oxide (IZO) nanofiber matrices are synthesized on SiO2-covered silicon substrates by the electrospinning method. The nanofibers’ dimensions, morphology, and crystalline structure are characterized by scanning electron microscopy, atomic force microscopy, and X-ray diffraction. The results of studying the electrical properties of nanofibers, as well as their sensitivity to UV radiation depending on the In-to-Zn concentration ratio, are presented. It is shown that the highest sensitivity to UV is observed at the indium content of about 50 atomic %. The photocurrent increment with respect to the dark current is more than 4 orders of magnitude. The response and recovery times are 60 and 500 sec, respectively. The results obtained suggest that IZO nanofibers can find application as UV sensors with improved characteristics.

scholarly journals Ultrashort Pulsed Laser Ablation of Magnesium Diboride: Plasma Characterization and Thin Films Deposition

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Angela De Bonis ◽  
Agostino Galasso ◽  
Antonio Santagata ◽  
Roberto Teghil
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Optical Emission ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Laser Target ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

A MgB2target has been ablated by Nd:glass laser with a pulse duration of 250 fs. The plasma produced by the laser-target interaction, showing two temporal separated emissions, has been characterized by time and space resolved optical emission spectroscopy and ICCD fast imaging. The films, deposited on silicon substrates and formed by the coalescence of particles with nanometric size, have been analyzed by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, micro-Raman spectroscopy, and X-ray diffraction. The first steps of the films growth have been studied by Transmission Electron Microscopy. The films deposition has been studied by varying the substrate temperature from 25 to 500°C and the best results have been obtained at room temperature.

Direct Imaging of Nanoparticle Embedding into PS Films

2002 ◽  
Vol 734 ◽  
Author(s):  
J.H. Teichroeb ◽  
J.A. Forrest
Keyword(s):  
Annealing Time ◽  
Sample Surface ◽  
Nano Particles ◽  
Silicon Substrates ◽  
Force Microscopy ◽  
Atomic Force ◽  
First Case ◽  
Large Numbers ◽  
20 Nm ◽  
Number Of Particles

ABSTRACTNon-contact Atomic Force Microscopy (AFM) was used to study the embedding of 10 nm and 20 nm gold nano-particles into the surface of polystyrene films spin-coated onto silicon substrates. The rate of embedding was determined by measuring the apparent nanosphere height as a function of annealing time. This was accomplished by two different methods. In the first case, each image (after a specific annealing time) is acquired at a different spot on the sample surface. In this case a fairly large (∼40) number of particles were imaged in order to have acceptable statistics. A second method involved the use of a kinematic mounting hot stage that allowed the same spot on the sample to be imaged at each time. This allows the same final precision without the same necessity for imaging large numbers of particles. The results indicate that sub nm resolution is easily obtainable with either technique.

Optical and Electrical Properties of SnS: Ag Films as Solar Cell Absorbers

2009 ◽  
Vol 60-61 ◽  
pp. 11-15 ◽  
Author(s):  
Pe Min Lu ◽  
Hong Jie Jia ◽  
Shu Ying Cheng
Keyword(s):  
X Ray Diffraction ◽  
Average Roughness ◽  
X Ray ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Atomic Force ◽  
Semiconducting Properties ◽  
Direct Band ◽  
Diffraction Peaks ◽  
P Type

SnS and Ag films were deposited on glass substrates by vacuum thermal evaporation successively, then they were annealed in N2 ambience at a temperature of 300 oC for 2h. By controlling the Ag evaporation voltage to roughly alter content of Ag in SnS films, different Ag-doped SnS films were obtained. The microstructures, composition and properties of the films were characterized with X-ray diffraction ( XRD ), atomic force microscopy(AFM) and some other methods. With the increase of Ag evaporation voltage (VAg), there exist new phases of Ag8SnS6 and Ag2S, whose intensity of diffraction peaks increases with the increasing Ag-dopant, and the average roughness of the films varies from 18.7nm to 23.6nm, and grain size increases from 192nm to 348nm. With the increase of VAg, the evaluated direct band gap Eg of the films decreases from 2.28eV(undoped) to 2.05eV (VAg=70V), the carrier concentration value and Hall mobility of the films diminishes from 2.048×1014cm-3 and 25.96 cm2.v-2.s-1 to 1.035×1016 cm-3 and 5.66 cm2.v-2.s-1, respectively; while the resistivity of the films decreases sharply from 1174Ω.cm(undoped ) to 107Ω.cm (VAg=70V ). All the films are of p-type conductivity. The above results show that the semiconducting properties of the SnS films have been improved by silver-doping.

scholarly journals Surface micromorphology analysis of Cu/Ni nanocomposite thin films by power spectra density and fractal geometry

2020 ◽  
Vol 38 (2) ◽  
pp. 328-333
Author(s):  
Kimia Nikpasand ◽  
Seyed Mohammad Elahi ◽  
Amir Hossein SarI ◽  
Arash Boochani
Keyword(s):  
Rf Sputtering ◽  
Power Spectra ◽  
Morphological Properties ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Power Spectral ◽  
Surface Micromorphology ◽  
Afm Analysis

AbstractCopper (Cu) and nickel (Ni) nanoparticles have been grown simultaneously on glass and silicon substrates by RF sputtering method to form three Cu/Ni nanocomposites at different deposition times. The existence of Cu and Ni peaks in the X-ray diffraction (XRD) profiles confirms the crystalline structure of samples with Cu and Ni atomic content which have also been characterized by Rutherford backscattering (RBS) method. Moreover, the structural and morphological properties of the prepared nanocomposites have been compared with respect to their morphologies by means of atomic force microscopy (AFM) analysis. In order to compare the surface roughness over different spatial frequency ranges and evaluate surface quality, power spectral density (PSD) of each sample has been extracted from AFM data and also, the experimental and theoretical results have been compared. The fractal nature of these nanocomposites has been finally discussed.

Effect of Sputtering Process Parameters on the Thermoelectric Properties of P and N-Type Bi2Te3 Films

2012 ◽  
Vol 185 ◽  
pp. 94-98
Author(s):  
Arina ◽  
Fan Shermin Chow Hui ◽  
Banu Abdul Bari Shamira ◽  
Ai Lin Chia ◽  
Ye Ko San ◽  
...  
Keyword(s):  
Thermoelectric Properties ◽  
Process Parameters ◽  
Room Temperature ◽  
Rf Magnetron Sputtering ◽  
X Ray Diffraction ◽  
Characterization Methods ◽  
Force Microscopy ◽  
Atomic Force ◽  
Argon Flow ◽  
P Type

Thermoelectric is an ever evolving field that serves many critical needs (cooling and power generation) in the industry. The key objective of this work is to fabricate Bismuth Telluride (Bi2Te3) thin-films by varying the various process parameters using a radio-frequency (RF) magnetron sputtering disposition technique. Characterization methods such as four point probe resistivity, surface profiler, atomic force microscopy (AFM), X-ray diffraction (XRD), Seebeck coefficient and thermal diffusivity are performed on the N and P-type Bi2Te3films. The samples are analysed for their electrical properties in relation to the evolved microstructures, for how the process parameters of sputtering and annealing affect these changes. The results demonstrate that N-Type film (S2) processed using sputtering parameters of 7mT, 100W, 50sccm of argon flow under room temperature for 30mins with no annealing and the P-Type film processed using sputtering parameters of 7mT, 100W, 60sccm under room temperature for 30mins with institute annealing at 200°C for 2h exhibit desirable thermoelectric properties suitable for cooling application in microelectronic and optoelectronic devices, optimizing their performance and reliability.

scholarly journals Surface and Optical Properties of Gd-Doped ZrO2 Nano Films

2020 ◽  
Vol 4 (1) ◽  
pp. 4
Author(s):  
Ognian Dimitrov ◽  
Irina Stambolova ◽  
Sasho Vassilev ◽  
Katerina Lazarova ◽  
Silvia Simeonova
Keyword(s):  
Thin Films ◽  
Rare Earth ◽  
Sol Gel ◽  
Earth Metal ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Average Roughness ◽  
Force Microscopy ◽  
Atomic Force ◽  
Skin Conditions

Nanosized coatings of ZrO2 were deposited on silicon substrates using sol-gel and spin coating techniques. The precursor solutions were prepared from ZrOCl2.8H2O with the addition of different percentage (0.5–5%) of rare earth Gd3+ ions as dopant. The thin films were homogeneous, with average thickness of 115 nm and refractive index (n) of 1.83. The X-ray diffraction analysis (XRD) revealed the presence of a varying mixture of monoclinic and tetragonal ZrO2 polycrystalline phases, depending on the dopant, all of which with nanosized crystallites. Scanning electron microscopy (SEM) as well as atomic force microscopy (AFM) methods were deployed to investigate the surface morphology and roughness of the thin films, respectively. They revealed a smooth, well uniform and crack-free surface with average roughness of 0.8 nm. It was established that the dopant concentration affects the photoluminescence (PL) properties of the samples. The undoped films exhibited broad violet-blue PL emission, while the addition of Gd3+ ions resulted in new narrow bands in both UV-B and visible light regions, characteristic of the rare earth metal. The intensive emission located at 313 nm can find useful application in medical lamps for treatment of different skin conditions.

MORPHOLOGY AND ELECTRICAL RESISTIVITY OF AuCu NANOFILM ALLOYS

2008 ◽  
Vol 15 (06) ◽  
pp. 881-888 ◽  
Author(s):  
R. D. MALDONADO ◽  
A. I. OLIVA
Keyword(s):  
Thin Films ◽  
Electrical Resistivity ◽  
Total Thickness ◽  
X Ray Diffraction ◽  
Atomic Concentration ◽  
Vacuum Oven ◽  
Force Microscopy ◽  
Atomic Force ◽  
Abrupt Changes ◽  
P Type

Au / Cu thin films (33–320 nm thickness) were deposited by thermal evaporation on p-type silicon (100) substrates. Two groups of these bimaterial films were alloyed into a vacuum oven by diffusion. The first group was prepared with 24% Au atomic concentration (i.e. 33, 96, 158, 224, and 320 nm as AuCu total thickness). The second group was prepared changing the Au atomic concentration from 10% to 90%, with 10% Au steps and similar total thickness (100 nm). Prepared alloys were characterized with atomic force microscopy (AFM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and collinear four-probe techniques in order to obtain their morphology, stoichiometry, crystalline structure, and electrical resistivity, respectively. Particularly, electrical resistivity presented abrupt changes with the atomic concentration and the annealing temperature with important differences as compared with pure Au and Cu thin films.

scholarly journals Effect the Temperature on Structure and Optical Properties for ZnS nanostructure Thin Film

2015 ◽  
Vol 11 (2) ◽  
pp. 3459-3472
Author(s):  
Nada K. Abbas ◽  
Khalid T. Al- Rasoul ◽  
Zainb J. Shanan
Keyword(s):  
Grain Size ◽  
Band Gap ◽  
Band Gap Energy ◽  
Temperature Reaction ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Zinc Blende ◽  
Absorption Studies ◽  
Two Peaks

ZnS nanocrystalline thin films by different temperature of reaction were prepared by chemical bath deposition using thiourea and zinc acetate as S2– and Zn2+ source. The optical absorption studies in the wavelength range 200–1100 nm show that band gap energy of samples 3.75 and 4.0 eV for different temperature reaction condition. The refractive index was estimated within the visible wavelength at 623 nm, it was 2.04 for sample 1 and its value will increase for sample 2 to be 2.55. The room temperature photoluminescence spectra of the films showed two peaks for all samples. We assigned the first peak due to band gap transitions while the latter was due to zinc vacancy in the films. Structural analysis using atomic force microscopy shows that the grain size for films were 73.2 and 87.34 nm. X-ray diffraction analysis indicates that both of them formed in the reaction bath have cubic zinc blende structure .The structural estimation shows variation in grain size 7nm and 20nm with different temperature reaction.

scholarly journals Influence of substrates on the properties of cerium -doped CdO nanocrystalline thin films

2018 ◽  
Vol 16 (38) ◽  
pp. 112-123
Author(s):  
Abubaker S. Mohammed
Keyword(s):  
Thin Films ◽  
Glass Substrate ◽  
Spray Pyrolysis Technique ◽  
Xrd Analysis ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Cerium Content ◽  
Atomic Force ◽  
Cdo Films

Transparent thin films of CdO:Ce has been deposited on to glass and silicon substrates by spray pyrolysis technique for various concentrations of cerium (2, 4, and 6 Vol.%). CdO:Ce films were characterized using different techniques such as X-ray diffraction (XRD), atomic force microscopy(AFM) and optical properties. XRD analysis show that CdO films exhibit cubic crystal structure with (1 1 1) preferred orientation and the intensity of the peak increases with increasing's of Ce contain when deposited films on glass substrate, while for silicon substrate, the intensity of peaks decreases, the results reveal that the grain size of the prepared thin film is approximately (73.75-109.88) nm various with increased of cerium content. With a surface roughness of (0.871–16.2) nm as well as root mean square of (1.06-19.7) nm for glass substrate, while for silicon (84.79-107.48) nm, for a pure CdO and doped with Ce (2, 4, and 6 Vol.%). The 300-nm-thin CdO films showed that the optical energy band gap equal 2.6 eV, and increases with increasing doping until reaches a maximum value of 3.25 eV when doping levels 6 Vol.%.

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