Effects of annealing temperature on a ZnO thin film-based ultraviolet photodetector

2021 ◽  
Author(s):  
Ümit Doğan ◽  
Fahrettin Sarcan ◽  
Kamuran Kara Koç ◽  
Furkan Kuruoğlu ◽  
Ayşe Erol

Abstract In this paper, the effects of annealing temperature on the performance of a ZnO thin film-based Metal-Semiconductor-Metal (MSM) type ultraviolet (UV) photodetector is reported. ZnO thin films were grown on a glass substrate using the Pulsed Filtered Cathodic Vacuum Arc Deposition (PFCVAD) technique at room temperature and after the deposition process the samples were annealed at 400, 450 and 550 °C in air condition to investigate the annealing effect on the structural, electrical, and optical properties of the photodetector. ZnO thin films which have grains in nanometer range has an increasing in the diameter of grains from 10.5 to 18.3 nm as a function of annealing temperature results in a red shift in the cut-off wavelength of the photodetector from 3.25 eV (381 nm) to 3.23 eV (383 nm). It is demonstrated that the sensitivity and the speed (rise/fall times) of the ZnO thin film based MSM photodetectors enhances with increasing post growth annealing temperature of ZnO thin film due to the increase in the absorption coefficient and the decrease of the total area of the grain boundaries due to the larger grain sizes formation in ZnO thin films with increasing thermal annealing temperature.

2021 ◽  
Vol 43 (3) ◽  
pp. 253-253
Author(s):  
Mehmet zkan Mehmet zkan ◽  
Sercen Sadik Erdem Sercen Sadik Erdem

In this paper, silver (Ag)doped Zinc Oxide(ZnO) thin films were prepared on glass and silicon substrate by using a thermionic vacuum arc technique. The surface, structural, optical characteristics of silver doped thin films have been examined by X-Ray diffractometer (XRD), field emission scanning emission electron microscopy (FESEM), atomic force microscopy (AFM), and UV-Visible spectrophotometer. As a result of these measurements, Ag, Zn and ZnO reflection planes were determined for thin films formed on Si and glass substrate. Nano crystallites have emerged in FESEM and AFM images. The produced films have low transparency. The optical band gap values were measured by photoluminescence devices at room temperature for thin films produced on silicon and glass substrate. The band gap values are very close to 3.10 eV for Ag doped ZnO thin films. The band gap of un-doped ZnO thin film is approximately 3.3 eV. It was identified that Ag doped changes the properties of the ZnO thin film.


2009 ◽  
Vol 23 (06n07) ◽  
pp. 1719-1724
Author(s):  
H. KAVAK ◽  
N. H. ERDOGAN ◽  
K. KARA ◽  
H. YANIS ◽  
Z. BAZ ◽  
...  

The transparent, conductive n and p -type semiconducting ZnO thin films were prepared by pulsed filtered cathodic vacuum arc deposition (PFCVAD) method. The structural, optical and electrical properties of n and p -type ZnO thin films are investigated after annealing at 450°C. 197 nm thick n -type ZnO thin film was deposited with oxygen pressure of 8.5 × 10-4 Torr . XRD pattern of annealed ZnO thin film exhibits hexagonal structure with (100), (101) and (110) orientations. The crystallite size of semiconductor ZnO thin film is 18 nm, interplanar distance 0.16 nm and lattice constant c is 0.52 nm for (110) orientation. The optical transmittance spectra of n and p -type ZnO films are over 90% in the visible wavelength region with optical energy gap 3.3 eV. p -type ZnO thin films are produced by oxidation of PFCVAD deposited zinc nitride. Zinc nitride is deposited with nitrogen pressure of 8.6 × 10-4 Torr and the thickness of this film is 179 nm. The oxidation of zinc nitride thin films at 450°C results in hexagonal structures p -type ZnO thin films. XRD pattern of this film has the same (100), (101) and (110) orientations with the same crystalline structures as the directly deposited ZnO thin film. Hall measurements indicated that ZnO films were p -type and the highest carrier concentration of 1.08 × 1018 cm -3 and mobility of 93.53 cm2/Vs were obtained.


2013 ◽  
Vol 667 ◽  
pp. 24-29
Author(s):  
Mohamad Hafiz Mamat ◽  
A.A.A. Halim ◽  
Mohd Zainizan Sahdan ◽  
S. Amizam ◽  
Zuraida Khusaimi ◽  
...  

The effect of annealing temperatures on the Zinc Oxide (ZnO) thin films properties has been investigated. 1.0 M ZnO solution was prepared by sol-gel method as coating solution for ZnO thin films deposition process. The thin films deposition was conducted by spin-coating technique on the silicon and glass substrates. The scanning electron microscopy (SEM) images reveal the evolution of ZnO surface morphology with annealing temperatures. The crystallinity improvement occurred at higher annealing temperature as shown by x-ray diffraction (XRD) result. The optical properties found to be varied at different annealing temperatures. The current-voltage (I-V) measurement results suggested the improvement of ZnO thin film electrical properties with annealing temperatures.


2008 ◽  
Vol 63 (7-8) ◽  
pp. 440-444 ◽  
Author(s):  
Mohammad Hossein Habibi ◽  
Mohammad Khaledi Sardashti

For effectively fabricating nanocrystalline ZnO thin films by the sol-gel method, the relationships between the temperature of the heat treatment and the quality of the ZnO thin films was observed. The decomposition of the sol was analyzed by TG-DTA. The orientation of the c-axis of the ZnO thin film was identified by XRD. The morphology was observed and estimated by SEM. The experimental results did show that the orientation of the c-axis is determined by the pre-heating and annealing temperatures, and that the grain size and roughness of the ZnO thin films are mainly influenced by the annealing temperature. A qualified ZnO thin film was prepared by using a sol-gel with a preheating temperature of 275 °C for 10 min and an annealing temperature of 550 °C for 60 min.


Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 397
Author(s):  
Yu-Chen Chang ◽  
Ying-Chung Chen ◽  
Bing-Rui Li ◽  
Wei-Che Shih ◽  
Jyun-Min Lin ◽  
...  

In this study, piezoelectric zinc oxide (ZnO) thin film was deposited on the Pt/Ti/SiNx/Si substrate to construct the FBAR device. The Pt/Ti multilayers were deposited on SiNx/Si as the bottom electrode and the Al thin film was deposited on the ZnO piezoelectric layer as the top electrode by a DC sputtering system. The ZnO thin film was deposited onto the Pt thin film by a radio frequency (RF) magnetron sputtering system. The cavity on back side for acoustic reflection of the FBAR device was achieved by KOH solution and reactive ion etching (RIE) processes. The crystalline structures and surface morphologies of the films were analyzed by X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM). The optimized as-deposited ZnO thin films with preferred (002)-orientation were obtained under the sputtering power of 80 W and sputtering pressure of 20 mTorr. The crystalline characteristics of ZnO thin films and the frequency responses of the FBAR devices can be improved by using the rapid thermal annealing (RTA) process. The optimized annealing temperature and annealing time are 400 °C and 10 min, respectively. Finally, the FBAR devices with structure of Al/ZnO/Pt/Ti/SiNx/Si were fabricated. The frequency responses showed that the return loss of the FBAR device with RTA annealing was improved from −24.07 to −34.66 dB, and the electromechanical coupling coefficient (kt2) was improved from 1.73% to 3.02% with the resonance frequency of around 3.4 GHz.


2014 ◽  
Vol 895 ◽  
pp. 41-44
Author(s):  
Seiw Yen Tho ◽  
Kamarulazizi Ibrahim

In this work, the influences of plasma pre-treatment on polyethylene terephthalate (PET) substrate to the properties of ZnO thin film have been carried out. ZnO thin films were successfully grown on PET substrate by spin coating method. In order to study the effects of plasma pre-treatment, a comparison of treated and untreated condition was employed. Water contact angle measurement had been carried out for PET wettability study prior to ZnO thin film coating. Morphology study of ZnO thin film was performed by scanning probe microscope (SPM). Besides, optical study of the ZnO thin film was done by using UV-vis spectrophotometer. All the measured results show that plasma pre-treatment of PET substrate plays an important role in enhancing the wettability of PET and optical properties of the ZnO thin films. In conclusion, pre-treatment of PET surface is essential to produce higher quality ZnO thin film on this particular substrate in which would pave the way for the integration of future devices.


Vacuum ◽  
2013 ◽  
Vol 89 ◽  
pp. 220-224 ◽  
Author(s):  
Zhanyun Huang ◽  
Ping Luo ◽  
Wanzong Chen ◽  
Shirong Pan ◽  
Dihu Chen

2011 ◽  
Vol 1288 ◽  
Author(s):  
Rashmi Menon ◽  
K. Sreenivas ◽  
Vinay Gupta

ABSTRACTZinc Oxide (ZnO), II-VI compound semiconductor, is a promising material for ultraviolet (UV) photon sensor applications due to its attractive properties such as good photoconductivity, ease processing at low temperatures and excellent radiation hardness. The rf magnetron sputtering is a suitable deposition technique due to better control over stoichiometry and deposition of uniform film. Studies have shown that the presence of surface defects in ZnO and subsequently their passivation are crucial for enhanced photo-response characteristics, and to obtain the fast response speed. Worldwide efforts are continuing to develop good quality ZnO thin films with novel design structures for realization of an efficient UV photon sensor. In the present work, UV photon sensor is fabricated using a ZnO thin films deposited by rf magnetron sputtering on the corning glass substrate. Photo-response, (Ion/Ioff) of as-grown ZnO film of thickness 100 nm is found to be 3×103 with response time of 90 ms for UV intensity of 140 μW/cm2 (λ = 365 nm). With irradiation on ZnO thin film by pulsed Nd:YAG laser (forth harmonics 266 nm), the sensitivity of the UV sensor is found to enhance. The photo-response increases after laser irradiation to 4x104 with a fast response speed of 35 ms and attributed to the change in surface states and the native defects in the ZnO thin film. Further, enhancement in the ultraviolet (UV) photo-response (8×104) of detector was observed after integrating the nano-scale islands of Sn metal on the surface of laser irradiated ZnO thin film.


2011 ◽  
Vol 25 (20) ◽  
pp. 2741-2749 ◽  
Author(s):  
J. C. ZHOU ◽  
L. LI ◽  
L. Y. RONG ◽  
B. X. ZHAO ◽  
Y. M. CHEN ◽  
...  

High transparency and conductivity of transparent conducting oxide thin film are very important for improving the efficiency of solar cells. ZnO thin film is a better candidate for transparent conductive layer of solar cell. N-type ZnO thin films were prepared by radio-frequency magnetron sputtering on glass substrates. ZnO thin films underwent annealing treatment after deposition. The influence of the sputtering power on the surface morphology, the electrical and optical properties were studied by AFM, XRD, UV2450 and HMS-3000. The experimental results indicate that the crystal quality of ZnO thin film is improved and all films show higher c-axis orientation with increasing sputtering power from 50 to 125 W. The average transparency of ZnO thin films is higher than 90% in the range of 400–900 nm between the sputtering power of 50–100 W. After the rapid thermal annealing at 550°C for 300 s under N2 ambient, the minimum resistivity reach to 10-2Ω⋅ cm .


2015 ◽  
Vol 1731 ◽  
Author(s):  
Chih-Hung Li ◽  
Jian-Zhang Chen ◽  
I-Chun Cheng

ABSTRACTWe investigated the electrical properties of the rf-sputtered HfxZn1-xO/ZnO heterostructures. The thermal annealing on ZnO prior to the HfxZn1-xO deposition greatly influences the properties of the heterostructures. A highly conductive interface formed at the interface between HfxZn1-xO and ZnO thin films as the ZnO annealing temperature exceeded 500°C, leading to the apparent decrease of the electrical resistance. The resistance decreased with an increase of either thickness or Hf content of the HfxZn1-xO capping layer. The Hf0.05Zn0.95O/ZnO heterostructure with a 200-nm-thick 600°C-annealed ZnO exhibits a carrier mobility of 14.3 cm2V-1s-1 and a sheet carrier concentration of 1.93×1013 cm-2; the corresponding values for the bare ZnO thin film are 0.47 cm2V-1s-1 and 2.27×1012 cm-2, respectively. Rf-sputtered HfZnO/ZnO heterostructures can potentially be used to increase the carrier mobility of thin-film transistors in large-area electronics.


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