Properties of ZnO Thin Films Grown on Si Substrates by Ultrasonic Spray and ZnO/Si Heterojunctions

2009 ◽  
Vol 609 ◽  
pp. 133-137 ◽  
Author(s):  
N. Zebbar ◽  
M.S. Aida ◽  
A.E.K. Hafdallah ◽  
O. Daranfad ◽  
H. Lekiket ◽  
...  

Experimental analysis of current –voltage and capacitance-voltage characteristics of n-ZnO/p-Si (100) heterostructures were presented. Undoped and In-doped ZnO films were deposited by the simple ultrasonic spray method on p-Si substrates (100) at varied substrate temperatures from 200 to 400°C. The structural and optical properties of ZnO films were investigated using X-ray diffraction (XRD) and transmission spectra respectively. The electrical conductivity is calculated from transport measurement in a two probes coplanar structure. It is found that the doped ZnO: In films have higher (002) diffraction peak than undoped ZnO. All films exhibit a high transparency about 85%. The maximum conductivity is observed at 350°C for doped films but increases with substrate temperature for undoped ones. Current–voltage (I-V) characteristics of all n-ZnO/p-Si heterojunctions exhibit non linear characteristics with a small current leakage in the reverse voltage. The obtained device shows a barrier height in the order of 0.65 eV, this is consistent with the theoretical value 0.67eV. The capacitance increases with increasing reverse bias in an approximately linear 1/C2-V relationship.

2014 ◽  
Vol 936 ◽  
pp. 618-623
Author(s):  
Lung Chien Chen ◽  
Xiu Yu Zhang ◽  
Kuan Lin Lee

Cu-doped ZnO (CZO) films have been widely discussed due to its potential applications in semiconductor devices, such as gas sensors or solar cells, but few articles were reported to show the effect on properties of CZO films by using different Cu sources. The article demonstrates that CZO films have been prepared by using different Cu source via a simple ultrasonic spray method, in which copper nitrate and copper acetate were used as copper sources. Optical properties of CZO films prepared by copper nitrate and copper acetate were investigated by transmittance and photoluminescence measurement. The X-ray diffraction analysis and field emission scanning electron microscopy were used to investigate the composition and the morphology of the films. The CZO films prepared by using copper acetate shows better optical properties by comprehensive analysis.


2013 ◽  
Vol 341-342 ◽  
pp. 237-241
Author(s):  
Wei Hua Huang ◽  
Guo Wen Zhong ◽  
Li Ping Su ◽  
Tan Li

Pure and Al-doped ZnO thin films were deposited by radio frequency magnetron sputtering at room temperature on n-(100) Si, fused quartz and Pt/Ti/SiO2/Si substrates. Structural, optical and electrical properties of the prepared thin films had been characterized. The X-ray diffraction results indicated that all the films had (002) preferential orientation. The AFM and SEM images showed that the surface of the films was smooth, crack-free and pore-free, the interface between the film and the substrate was sharp and distinct. From the transmission data the band gap energy Eg of the film increased when doped with Al2O3, and the transparent was still high (above 80%). The current voltage characteristics indicated that doping with Al2O3, the leakage current of ZnO thin films increased rapidly and the films acted as a conductive.


Electronics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 446 ◽  
Author(s):  
Ya-Fen Wei ◽  
Wen-Yaw Chung ◽  
Cheng-Fu Yang ◽  
Jei-Ru Shen ◽  
Chih-Cheng Chen

ZnO films with a thickness of ~200 nm were deposited on SiO2/Si substrates as the seed layer. Then Zn(NO3)2-6H2O and C6H12N4 containing different concentrations of Eu(NO3)2-6H2O or In(NO3)2-6H2O were used as precursors, and a hydrothermal process was used to synthesize pure ZnO as well as Eu-doped and In-doped ZnO nanowires at different synthesis temperatures. X-ray diffraction (XRD) was used to analyze the crystallization properties of the pure ZnO and the Eu-doped and In-doped ZnO nanowires, and field emission scanning electronic microscopy (FESEM) was used to analyze their surface morphologies. The important novelty in our approach is that the ZnO-based nanowires with different concentrations of Eu3+ and In3+ ions could be easily synthesized using a hydrothermal process. In addition, the effect of different concentrations of Eu3+ and In3+ ions on the physical and optical properties of ZnO-based nanowires was well investigated. FESEM observations found that the undoped ZnO nanowires could be grown at 100 °C. The third novelty is that we could synthesize the Eu-doped and In-doped ZnO nanowires at temperatures lower than 100 °C. The temperatures required to grow the Eu-doped and In-doped ZnO nanowires decreased with increasing concentrations of Eu3+ and In3+ ions. XRD patterns showed that with the addition of Eu3+ (In3+), the diffraction intensity of the (002) peak slightly increased with the concentration of Eu3+ (In3+) ions and reached a maximum at 3 (0.4) at%. We show that the concentrations of Eu3+ and In3+ ions have considerable effects on the synthesis temperatures and photoluminescence properties of Eu3+-doped and In3+-doped ZnO nanowires.


2012 ◽  
Vol 557-559 ◽  
pp. 1984-1987
Author(s):  
Hui Qun Zhu ◽  
Yu Ming Li ◽  
Jun Long Li ◽  
Ling Sun

P-doped ZnO thin films were prepared on different Si substrates by RF magnetron sputtering in Ar and O2 mixed atmosphere. The P-doped ZnO films were changed from n-type to p-type by phosphorus diffusing from the n-Si substrates with higher phosphorus concentration into the ZnO films during depositing. The crystal structure of the ZnO films was examined by X-ray diffraction and confirmed to belong to wurtzite and highly c-axis oriented primarily perpendicular to the substrate. The Hall effect measurement results show that the corresponding hole concentration and risistivity of the P-doped ZnO film was 8.982×1017 cm-3 and 1.489 Ω•cm respectively. This reveals that the P-doped ZnO thin film is really p-type behavior.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Prashant Pradhan ◽  
Juan Carlos Alonso ◽  
Monserrat Bizarro

ZnO and Al doped ZnO films were produced by spray pyrolysis. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis spectroscopy, and photoluminescence. Their photocatalytic activity was evaluated by the decomposition of the methyl orange dye using different light sources: ultraviolet light, artificial white light, and direct sunlight. The films were also tested under darkness for comparison. The ZnO films were able to degrade the test pollutant under UV and sunlight in more than a 60% after 180 min of irradiation and a scarce degradation was obtained using white light. However, the Al doped ZnO films presented a very high degradation rate not only under UV and sunlight (100% degradation), but also under white light (90% degradation after the same irradiation time). An unexpected high degradation was also obtained in the dark, which indicates that a nonphotonic process is taking place parallel to the photocatalytic process. This can be due to the extra electrons—provided by the aluminum atoms—that migrate to the surface and produce radicals favoring the decomposition process even in the dark. The high activity achieved by the ZnO: Al films under natural conditions can be potentially applied to water treatment processes.


2012 ◽  
Vol 560-561 ◽  
pp. 820-824
Author(s):  
Yue Zhi Zhao ◽  
Fei Xiong ◽  
Guo Mian Gao ◽  
Shi Jing Ding

Mn-doped ZnO thin films were prepared on SiO2substrates by using a radio-frequency(rf) magnetron sputtering in order to investigate structure and optical proprieties of the films. X-ray diffraction (XRD), Atomic force microscope (AFM) and UV-VIS spectrophotometry were employed to characterize the Mn-doped ZnO films. The results showed that the shape of the XRD spectrum was remarkably similar to that of the un-doped ZnO film; the film had mainly (002) peak, and indicate that the structure of the films was not disturbed by Mn-doped. The film had rather flat surfaces with the peak-to-tail roughness of about 25nm. Mn-doping changed the band gap of the films, which increased with the increase of the Mn content.


2005 ◽  
Vol 862 ◽  
Author(s):  
Kanji Yasui ◽  
Jyunpei Eto ◽  
Yuzuru Narita ◽  
Masasuke Takata ◽  
Tadashi Akahane

AbstractThe crystal growth of SiC films on (100) Si and thermally oxidized Si (SiO2/Si) substrates by hot-mesh chemical vapor deposition (HMCVD) using monomethylsilane as a source gas was investigated. A mesh structure of hot tungsten (W) wire was used as a catalyzer. At substrate temperatures above 750°C and at a mesh temperature of 1600°C, 3C-SiC crystal was epitaxially grown on (100) Si substrates. From the X-ray rocking curve spectra of the (311) peak, SiC was also epitaxially grown in the substrate plane. On the basis of the X-ray diffraction (XRD) measurements, on the other hand, the growth of (100)-oriented 3C-SiC films on SiO2/Si substrates was determined to be achieved at substrate temperatures of 750-800°C, while polycrystalline SiC films, at substrate temperatures above 850°C. From the dependence of growth rate on substrate temperature and W-mesh temperature, the growth mechanism of SiC crystal by HMCVD was discussed.


2020 ◽  
Vol 978 ◽  
pp. 384-389
Author(s):  
Sritama Roy ◽  
Saswati Soumya Dash ◽  
Prasanna Kumar Sahu ◽  
Smita Mishra ◽  
Jyoti Prakash Kar

Zinc Oxide (ZnO) thin films were produced by the sol gel dip coating process on the p-type silicon substrate with various withdrawal speeds changing from 1 to 4 cm/min, respectively. The films were annealed at a temperature of 500 °C for an hour in air ambient. The thin film thickness was found to be raised with the rise in withdrawal speed. The uniform distribution of the grains was appeared for all the films. The evolution of c-axis oriented (002) peak was revealed from X-ray diffraction (XRD) studies. The microstructural and optical properties of ZnO films were investigated by Raman, FTIR and photoluminescence spectroscopy (PL). The resistive switching properties of ZnO based memristors were studied by performing the current-voltage (I-V) measurements, where the thin films coated with lower withdrawal speed, have shown better switching property with rapid rise and fall of current during SET and RESET process, respectively.


2013 ◽  
Vol 669 ◽  
pp. 181-184
Author(s):  
Nan Ding ◽  
Li Ming Xu ◽  
Bao Jia Wu ◽  
Guang Rui Gu

Zinc oxide (ZnO) films were prepared on Si substrates and then aluminum nitride (AlN) films were deposited on ZnO films by radio frequency (RF) magnetron sputtering. The crystal orientation, crystallite structure and surface morphology of AlN/ZnO films were characterized by X-ray diffraction (XRD), Raman spectrum and scanning electron microscopy (SEM). It was indicated that the AlN films were closely deposited on the ZnO film and had good crystallinity. Moreover, about 1μm-sized crystal particles with high c-axial orientation distributed uniformly on the AlN/ZnO film surface. It was indicated that ZnO could be a promising candidate as buffer layer for preparation of AlN thin films.


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