DEPENDENCE OF TEMPERATURE ON THE STRUCTURE AND PHOTOLUMINESCENCE OF ZnO THIN FILMS FABRICATED BY PULSED Nd:YAG LASER DEPOSITION ON SAPPHIRE SUBSTRATES

2007 ◽  
Vol 21 (11) ◽  
pp. 1851-1860 ◽  
Author(s):  
XIAN QI WEI ◽  
BAO-YUAN MAN

Zinc oxide ( ZnO ) thin films were grown on sapphire substrates at different deposition temperatures by pulsed laser deposition (PLD). The structure, composition and optical properties of deposited thin films have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), Raman and photoluminescence (PL) spectra. The results show that the ZnO thin films deposited at 500°C have the best crystalline quality with hexagonal structure, surface morphology and stoichiometric composition. The PL spectrum reveals that the sample possesses the strongest ultraviolet (UV) emission at 370 nm and the weakest blue emission at 459 nm under this condition. Raman spectra and weak blue emission of PL spectra show that very few oxygen vacancies exist in the ZnO thin films.

2011 ◽  
Vol 383-390 ◽  
pp. 6289-6292
Author(s):  
Jian Ting He ◽  
Bo Xue Tan ◽  
Qin Qin Wei ◽  
Yuan Bin Su ◽  
Shu Lian Yang

ZnO thin films were deposited on n-Si (111) substrates at various oxygen partial pressures by pulsed laser deposition (PLD). X-ray diffraction (XRD), scanning electron microscopy (SEM) were used to analyze the influence of the oxygen partial pressure on the crystallization and morphology of the ZnO thin films. An optimal crystallized ZnO thin film was observed at the oxygen partial pressure of 6.5Pa. X-ray photoelectron spectroscopy (XPS) was used to analyze the surface components and distribution status of various elments in ZnO thin films. It was found that ZnO thin films were grown in Zn-rich state.


1997 ◽  
Vol 12 (6) ◽  
pp. 1433-1436 ◽  
Author(s):  
A. Iembo ◽  
F. Fuso ◽  
E. Arimondo ◽  
C. Ciofi ◽  
G. Pennelli ◽  
...  

RuO2 thin films have been produced on silicon-based substrates by in situ pulsed laser deposition for the first time. The electrical properties, the surface characteristics, the crystalline structure, and the film-substrate interface of deposited samples have been investigated by 4-probe resistance versus temperature technique, scanning electron microscopy, x-ray photoelectron spectroscopy, x-ray diffraction, and transmission electron microscopy, respectively. The films show good electrical properties. The RuO2-substrate interface is very thin (≈3 nm), since it is not degraded by any annealing process. These two characteristics render our films suitable to be used as electrodes in PZT-based capacitors.


Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 777 ◽  
Author(s):  
Angela De Bonis ◽  
Agostino Galasso ◽  
Alessandro Latini ◽  
Julietta V. Rau ◽  
Antonio Santagata ◽  
...  

Chromium borides are promising candidates for several structural applications including protective coatings for materials exposed to corrosive and abrasive environments. In this paper the pulsed laser deposition of chromium diboride-rich thin films has been carried out in vacuum by using a frequency doubled Nd:glass laser with a pulse duration of 250 fs. The films have been deposited at different substrate temperatures and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. Lastly, the film’s hardness has been studied by Vickers indentation technique. The results indicate that only the films deposited at a substrate temperature of 500 °C are crystalline and formed by chromium diboride, together with a certain amount of boron and chromium, which suggests that, as main mechanism, a process taking place on the surface from atoms and ions from the gas phase. This hypothesis has been confirmed by the study of the plasma produced by the ablation process.


2011 ◽  
Vol 383-390 ◽  
pp. 6293-6296 ◽  
Author(s):  
Jian Ting He ◽  
Bo Xue Tan ◽  
Yuan Bin Su ◽  
Shu Lian Yang ◽  
Qin Qin Wei

Highly c-axis oriented ZnO thin films were deposited on n-Si (111) substrate at various oxygen partial pressures by pulsed laser deposition (PLD). X-ray diffraction (XRD), Atomic force microscopy (AFM) were used to analyze the influence of the oxygen partial pressure on the crystallization and morphology of the ZnO thin films. X-ray photoelectron spectroscopy (XPS) was used to analyze relationships between chemical shifts of XPS energy spectra and stoichiometric ratios of ZnO thin films, and quantitative relationships between content of Zn, O and oxygen partial pressures. An optimal crystallized and stoichiometric ZnO thin film was observed at the oxygen partial pressure of 6.5Pa.


Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1282 ◽  
Author(s):  
Zhao ◽  
Li ◽  
Ai ◽  
Wen

A kind of devices Pt/Ag/ZnO:Li/Pt/Ti with high resistive switching behaviors were prepared on a SiO2/Si substrate by using magnetron sputtering method and mask technology, composed of a bottom electrode (BE) of Pt/Ti, a resistive switching layer of ZnO:Li thin film and a top electrode (TE) of Pt/Ag. To determine the crystal lattice structure and the Li-doped concentration in the resulted ZnO thin films, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) tests were carried out. Resistive switching behaviors of the devices with different thicknesses of Li-doped ZnO thin films were studied at different set and reset voltages based on analog and digital resistive switching characteristics. At room temperature, the fabricated devices represent stable bipolar resistive switching behaviors with a low set voltage, a high switching current ratio and a long retention up to 104 s. In addition, the device can sustain an excellent endurance more than 103 cycles at an applied pulse voltage. The mechanism on how the thicknesses of the Li-doped ZnO thin films affect the resistive switching behaviors was investigated by installing conduction mechanism models. This study provides a new strategy for fabricating the resistive random access memory (ReRAM) device used in practice.


1992 ◽  
Vol 7 (10) ◽  
pp. 2639-2642 ◽  
Author(s):  
R.K. Singh ◽  
Deepika Bhattacharya ◽  
S. Sharan ◽  
P. Tiwari ◽  
J. Narayan

We have fabricated Ni3Al and NiAl thin films on different substrates by the pulsed laser deposition (PLD) technique. A high energy nanosecond laser beam was directed onto Ni–Al (NiAl, Ni3Al) targets, and the evaporated material was deposited onto substrates placed parallel to the target. The substrate temperature was varied between 300 and 400 °C, and the substrate-target distance was maintained at approximately 5 cm. The films were analyzed using scanning electron microscopy, transmission electron microscopy, x-ray diffraction, and Rutherford backscattering spectrometry. At energy densities slightly above the evaporation threshold, a slight enrichment of Al was observed, while at higher energy densities the film stoichiometry was close (<5%) to the target composition. Barring a few particles, the surface of the films exhibited a smooth morphology. X-ray and TEM results corroborated the formation of Ni3Al and NiAl films from similar target compositions. These films were characterized by small randomly oriented grains with grain size varying between 200 and 400 Å.


2019 ◽  
Vol 9 (21) ◽  
pp. 4509
Author(s):  
Weijia Yang ◽  
Fengming Wang ◽  
Zeyi Guan ◽  
Pengyu He ◽  
Zhihao Liu ◽  
...  

In this work, we reported a comparative study of ZnO thin films grown on quartz glass and sapphire (001) substrates through magnetron sputtering and high-temperature annealing. Firstly, the ZnO thin films were deposited on the quartz glass and sapphire (001) substrates in the same conditions by magnetron sputtering. Afterwards, the sputtered ZnO thin films underwent an annealing process at 600 °C for 1 h in an air atmosphere to improve the quality of the films. X-ray diffraction, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet-visible spectra, photoluminescence spectra, and Raman spectra were used to investigate the structural, morphological, electrical, and optical properties of the both as-received ZnO thin films. The ZnO thin films grown on the quartz glass substrates possess a full width of half maximum value of 0.271° for the (002) plane, a surface root mean square value of 0.50 nm and O vacancies/defects of 4.40% in the total XPS O 1s peak. The comparative investigation reveals that the whole properties of the ZnO thin films grown on the quartz glass substrates are comparable to those grown on the sapphire (001) substrates. Consequently, ZnO thin films with high quality grown on the quartz glass substrates can be achieved by means of magnetron sputtering and high-temperature annealing at 600 °C.


1998 ◽  
Vol 533 ◽  
Author(s):  
Glenn G. Jernigan ◽  
Conrad L. Silvestre ◽  
Mohammad Fatemi ◽  
Mark E. Twigg ◽  
Phillip E. Thompson

AbstractThe use of Sb as a surfactant in suppressing Ge segregation during SiGe alloy growth was investigated as a function of Sb surface coverage, Ge alloy concentration, and alloy thickness using xray photoelectron spectroscopy, x-ray diffraction, and transmission electron microscopy. Unlike previous studies where Sb was found to completely quench Ge segregation into a Si capping layer, we find that Sb can not completely prevent Ge segregation while Si and Ge are being co-deposited. This results in the production of a non-square quantum well with missing Ge at the beginning and extra Ge at the end of the alloy. We also found that Sb does not relieve strain in thin films but does result in compositional or strain variations within thick alloy layers.


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