Features of interpretation of luminescence spectra of zinc oxide films on sapphire

2020 ◽  
Vol 10 ◽  
pp. 28-33
Author(s):  
A. M. Ismailov ◽  
◽  
A. E. Muslimov ◽  
Keyword(s):  
Luminescence Band ◽  
Complex Analysis ◽  
Local Heating ◽  
Luminescence Spectra ◽  
Zno Films ◽  
Recrystallization Annealing ◽  
Interstitial Zinc ◽  
Zinc Oxide Films ◽  
Oxygen Medium ◽  
Substrate Temperatures

In the presented work features of interpretation of luminescent spectral dependence properties of ZnO films on sapphire are given. For complex analysis, films of ZnO of different thickness obtained in oxygen medium at different substrate temperatures are considered using the stage of recrystallysis annealing. It is shown that only a red (650 – 1000 nm) band ZnO sapphire substrate is observed in the spectrum of cathodoluminescence of thin films obtained at low temperature of the substrate, and luminescence of the film ZnO fed by excessive defect. Prolonged recrystallization annealing results in improved quality of thin ZnO films and a broad (430 – 740 nm) band in the ZnO. With an increase the film thickness, only bands associated with ZnO appear in the cathodoluminescence spectra: the edge luminescence band (maximum 390 nm) and the red band (500 – 950 nm with a maximum in the region of 710 nm) are associated with charged zinc vacancies. Focusing the beam leads to local heating of the sample and an increase in the concentration of interstitial zinc. This is due to the displacement of the edge light band into the 410 nm region, as well as the blue mixing of the defective luminescence band.

scholarly journals Формирование кристаллических слоев Cu-=SUB=-2-=/SUB=-O и ZnO методом магнетронного распыления и их оптическая характеризация

2018 ◽  
Vol 52 (3) ◽  
pp. 402
Author(s):  
В.Ф. Агекян ◽  
Е.В. Борисов ◽  
А.С. Гудовских ◽  
Д.А. Кудряшов ◽  
А.О. Монастыренко ◽  
...  
Keyword(s):  
Substrate Temperature ◽  
Oxide Films ◽  
Optical Methods ◽  
Luminescence Spectra ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Zinc Oxide Films ◽  
Quartz Substrates ◽  
Substrate Temperatures

AbstractCopper (I) oxide and zinc oxide films are formed on silicon and glassy quartz substrates by magnetron assisted sputtering. The thickness of the films is tens and hundreds of nanometers. The films are grown at different substrate temperatures and different oxygen pressures in the working chamber. The film samples are studied by the X-ray diffraction technique, scanning electron microscopy, and optical methods. It is established that an increase in the substrate temperature yields a change in the surface morphology of copper (I) oxide films towards the formation of well-pronounced crystallites. The reflectance and Raman spectra suggest that the quality of such films is close to that of bulk Cu_2O crystals produced by the oxidation of copper. As concerns ZnO films, an increase in the substrate temperature and an increase in the partial oxygen pressure make it possible to produce films, for which a sharp exciton structure is observed in the reflectance spectra and the emission of excitons bound at donors is observed in the luminescence spectra.

Characterization of Pulsed Laser Deposited Zinc Oxide

1992 ◽  
Vol 276 ◽  
Author(s):  
N. J. Ianno ◽  
L. McConville ◽  
N. Shaikh
Keyword(s):  
Zinc Oxide ◽  
Pulsed Laser ◽  
Laser Wavelength ◽  
Piezoelectric Response ◽  
Zno Films ◽  
Zinc Oxide Films ◽  
Substrate Temperatures ◽  
532 Nm ◽  
Deposited Films

ABSTRACTThe pulsed laser deposition of zinc oxide films (ZnO) has been studied as a function of laser wavelength, and substrate temperature. The deposited films were characterized by x-ray diffractometry, Auger electron spectroscopy, and scanning electron microscopy. Highly textured (002) ZnO films have been deposited at substrate temperatures of 300 C with laser wavelengths of 532 nm and 248 nm. However, the energy fluence of 248 nm radiation controls the degree of texturing, allowing highly textured films to be deposited at room temperature.Smart structures based on embedded, textured ZnO coated fibers, and wires exhibit excellent piezoelectric response to external stress.

Analysis of Sputtered Zinc Oxide Films

1980 ◽  
Vol 38 ◽  
pp. 416-417
Author(s):  
T. A. Emma ◽  
M. P. Singh
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Piezoelectric Materials ◽  
Oxide Films ◽  
Optical Quality ◽  
Zno Films ◽  
Rf Power ◽  
X Ray Diffraction ◽  
Sputtered Films ◽  
Zinc Oxide Films

Optical quality zinc oxide films have been characterized using reflection electron diffraction (RED), replication electron microscopy (REM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Significant microstructural differences were observed between rf sputtered films and planar magnetron rf sputtered films. Piezoelectric materials have been attractive for applications to integrated optics since they provide an active medium for signal processing. Among the desirable physical characteristics of sputtered ZnO films used for this and related applications are a highly preferred crystallographic texture and relatively smooth surfaces. It has been found that these characteristics are very sensitive to the type and condition of the substrate and to the several sputtering parameters: target, rf power, gas composition and substrate temperature.

Low Temperature Deposition of Zinc Oxide Films

2003 ◽  
Vol 763 ◽  
Author(s):  
H. W. Lee ◽  
Y. G. Wang ◽  
S. P. Lau ◽  
B. K. Tay
Keyword(s):  
Zinc Oxide ◽  
Carrier Concentration ◽  
Vacuum Arc ◽  
Zno Films ◽  
Al Alloy ◽  
Pure Zinc ◽  
Zinc Oxide Films ◽  
Alloy Target ◽  
Temperature Deposition ◽  
Filtered Cathodic Vacuum Arc

AbstractA detailed study of zinc oxide (ZnO) films prepared by filtered cathodic vacuum arc (FCVA) technique was carried out. To deposit the films, a pure zinc target was used and O2 was fed into the chamber. The electrical properties of both undoped and Al-doped ZnO films were studied. For preparing the Al-doped films, a Zn-Al alloy target with 5 wt % Al was used. The resistivity, Hall mobility and carrier concentration of the samples were measured. The lowest resistivity that can be achieved with undoped ZnO films was 3.4×10-3 Ωcm, and that for Al-doped films was 8×10-4 Ωcm. The carrier concentration was found to increase with Al doping.

Characteristics of Zinc Oxide Film Prepared by Chemical Bath Deposition Method

2014 ◽  
Vol 602-603 ◽  
pp. 871-875
Author(s):  
Yen Pei Fu ◽  
Jian Jhih Chen
Keyword(s):  
Thin Film ◽  
Zinc Oxide ◽  
Chemical Bath Deposition ◽  
Deposition Time ◽  
Oxide Films ◽  
Hexagonal Structure ◽  
Zno Films ◽  
Zinc Oxide Film ◽  
Incident Wavelength ◽  
Zinc Oxide Films

In this study, ZnO films, prepared by Chemical Bath Deposition (CBD), are applied as the conductive layers for thin film solar cells. Zinc acetate is used as a source of zinc, and different proportions of ammonia solution are added and well mixed. The growth of zinc oxide films in reaction solutions is taken place at 80°C and then heated to 500°C for one hour. In this study, the different ammonia concentrations and deposition times is controlled. The thin film structure is Hexagonal structure, which is determined by X-ray diffraction spectrometer (XRD) analysis. Scanning electron microscopy (SEM) is used as the observation of surface morphology, the bottom of the film is the interface where the heterogeneous nucleation happens. With the increase of deposition time, there were a few attached zinc oxide particles, which is formed by homogeneous nucleation. According to UV / visible light (UV / Vis) absorption spectrometer transmittance measurements and the relationship between/among the incident wavelength, it can be converted to the energy gaps (Eg), which are about 3.0 to 3.2eV, by using fluorescence spectroscopy analysis. The emission of zinc oxide films has two wavelengths which are located on 510nm and 570nm. According to Based on the all analytic results, the ammonia concentration at 0.05M, and the deposition time is 120 minutes, would obtain the conditions of ZnO films which is more suitable for applications of conductive layer material in thin film solar cell.

Change in polarity of zinc oxide films grown on sapphire substrates without insertion of any buffer layer

2008 ◽  
Vol 23 (12) ◽  
pp. 3269-3272 ◽  
Author(s):  
Yutaka Adachi ◽  
Naoki Ohashi ◽  
Tsuyoshi Ohnishi ◽  
Takeshi Ohgaki ◽  
Isao Sakaguchi ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Zno Films ◽  
Ion Scattering ◽  
Ceramic Target ◽  
Interfacial Phase ◽  
Sapphire Substrates ◽  
Zinc Oxide Films ◽  
Ion Scattering Spectroscopy ◽  
Doped Zno ◽  
Polarity Change

We have investigated the polarity of zinc oxide (ZnO) and Al-doped ZnO films grown on (11¯20) and (0001) sapphire substrates, using coaxial impact collision ion scattering spectroscopy. The films grown by pulsed laser deposition with a nominally undoped ZnO ceramic target had a (000¯1) surface, whereas the films prepared with a 1 mol% Al-doped ZnO ceramic target had a (0001) surface. The usage of Al-doped and undoped targets caused no difference in the in-plane lattice orientation. Electron microscope observations revealed that polarity change due to doping occurred without the formation of any interfacial phase between ZnO and sapphire.

ELECTRICAL AND OPTICAL PROPERTIES OF MULTILAYER SOL GEL ZnO COATINGS

2006 ◽  
Vol 20 (23) ◽  
pp. 3357-3364 ◽  
Author(s):  
TALAAT MOUSSA HAMMAD
Keyword(s):  
Carrier Mobility ◽  
Sol Gel ◽  
Dip Coating ◽  
Free Carrier ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Electrical And Optical Properties ◽  
Zinc Oxide Films ◽  
Free Carrier Density ◽  
Fine Microstructure

Multilayer transparent conducting zinc oxide films have been prepared on boro-silicate substrates by the commercially sol gel dip coating process. Each layer was fired at 550°C in a conventional furnace for 15 min. The final coatings were then tempered under a flux of forming gas ( N 2/ H 2) at 400°C for 2 h. The coatings were characterized by surface stylus profiling and optical spectroscopy (UV-NIR). Results show that (1) ZnO films with electrical resistivity of 6×10-4 Ω· cm , free carrier mobility of approximately 77 cm 2/ V · s and free carrier density of approximately 6.14×1019 cm -3 are obtained for multilayers 310 nm and (2) the transmittance is approximately 60.4% and the reflectance is nearly 34.7% are obtained at a wavelength of 800 nm when the thickness of the ZnO multilayers is 310 nm. The crystal structure and grain orientation of ZnO films were determined by X-ray diffraction. SEM investigations revealed that the surface morphology of growing ZnO films on boro-silicate substrate is dominated by the smooth surface with a fine microstructure.

Electrical Properties of Pulsed Laser Deposited ZnO Thin Films

2009 ◽  
Vol 67 ◽  
pp. 121-125
Author(s):  
Chattopadhyay Sourav ◽  
Kumar Nath Tapan
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Substrate Temperature ◽  
Hall Mobility ◽  
Pulsed Laser ◽  
Deposition Process ◽  
Zno Thin Films ◽  
Zno Films ◽  
Visible Absorption ◽  
Substrate Temperatures

Epitaxial Single-crystal ZnO thin films have been grown on c-plane (0001) sapphire by Pulsed Laser Deposition process at different substrate temperatures (300 – 800 °C) with 10-1 mbar oxygen pressure. The thicknesses of the films have been varied by varying number of pulses with a repetition rate of 10 pulse/sec. It is found that the sheet resistivity of ZnO thin films grown on c-plane sapphires are in the order of 10-2 Ω-cm and it increases with increasing substrate temperatures and film thickness. The carrier concentrations and Hall mobility are found to be in the order of 1017 cm-3 and ~195 cm2/V-s, respectively. The Hall mobility slightly decreases with increase of substrate temperature and thickness of the films. It is also found that the ZnO films are structurally uniform and well oriented with perfect wurtzite structure with c/a ratio 5.1. We have also deposited non-epitaxial ZnO films on (100) p-Silicon substrates at the same conditions. From HR FE-SEM micrographs, surface morphology of ZnO films grown at lower substrate temperature are found to be uniform compared to the films grown at higher temperatures showing non-uniformity and misoriented wurtzite structures. However, the surface morphology of ZnO flims grown epitaxially on (0001) sapphire are found to be more uniform and it does not change much with growth temperature. The resistivity of the films grown on p-Silicon at higher temperatures is in the order of 103 Ω-cm whereas films grown at lower substrate temperatures show comparatively lower resistivities (~ 102 Ω-cm). From the recorded UV-Visible absorption spectrum the band gap of the film has been estimated to be 3.38 eV.

Why do the luminescence maxima of isostructural palladium(II) and platinum(II) complexes shift in opposite directions?

2014 ◽  
Vol 92 (10) ◽  
pp. 958-965 ◽  
Author(s):  
Stéphanie Poirier ◽  
Philippe Guionneau ◽  
Dominique Luneau ◽  
Christian Reber
Keyword(s):  
Polyvinyl Alcohol ◽  
Crystal Structures ◽  
Polymer Films ◽  
Luminescence Band ◽  
Luminescence Spectra ◽  
Temperature Dependent ◽  
Positive Shift ◽  
Increasing Temperature

Temperature-dependent luminescence spectra for a series of palladium(II) and platinum(II) complexes with thiocyanate, halide, and dithiocarbamate ligands are presented. All complexes show broad d−d luminescence. Crystal structures are reported for (n-Bu4N)2[Pt(SCN)4] and (n-Bu4N)2[Pd(SCN)4] at 150 and 250 K, for the palladium(II) dimethyldithiocarbamate (MeDTC) complex [Pd(MeDTC)2] at 150 and 300 K, and for its platinum(II) analog at 100 and 300 K. The structures of (n-Bu4N)2[Pt(SCN)4], (n-Bu4N)2[Pd(SCN)4], and [Pt(MeDTC)2] show similar volume increases with temperature. In contrast, the luminescence band maxima of palladium(II) and platinum(II) complexes have opposite shifts with increasing temperature. (n-Bu4N)2[Pd(SCN)4] shows a shift of −2.0 cm−1/K and [Pd(MeDTC)2] a shift of −1.1 cm−1/K, while both platinum(II) complexes have a positive shift of +1.6 cm−1/K. Calculated luminescence spectra with adjustable parameters reproduce the experimental spectra. The variation of their parameters with temperature shows the origin of different trends. Temperature-dependent luminescence spectra of [Pd(SCN)4]2− and [Pt(SCN)4]2− in polymer films of polyvinyl alcohol were measured. No clearcut shifts of maxima were observed for either compound, and their spectra are broader due to the disordered environment.

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