scholarly journals Enhanced Electrical Properties of Alkali-Doped ZnO Thin Films with Chemical Process

Solar ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 30-40
Author(s):  
Jaime G. Cuadra ◽  
Samuel Porcar ◽  
Diego Fraga ◽  
Teodora Stoyanova-Lyubenova ◽  
Juan B. Carda
Keyword(s):  
Electrical Properties ◽  
Large Scale ◽  
Low Cost ◽  
Light Trapping ◽  
Hexagonal Phase ◽  
Optical Transmittance ◽  
Zno Films ◽  
Spray Pyrolysis Method ◽  
Axis Orientation ◽  
Doped Zno

Doped ZnO are among the most attractive transparent conductive oxides for solar cells because they are relatively cheap, can be textured for light trapping, and readily produced for large-scale coatings. Here, we focus on the development of alternative Na and K-doped ZnO prepared by an easy low-cost spray pyrolysis method for conducting oxide application. To enhance the electrical properties of zinc oxide, alkali-doped Zn1−x MxO (x = 0.03) solid solutions were investigated. The resulting layers crystallize in a single hexagonal phase of wurtzite structure with preferred c-axis orientation along a (002) crystal plane. Dense, well attached to the substrate, homogeneous and highly transparent layers were obtained with great optical transmittance higher than 80%. The optical energy band gap of doped ZnO films increase from 3.27 to 3.29 eV by doping with Na and K, respectively. The electrical resistivity of the undoped ZnO could be decreased from 1.03 × 10−1 Ω.cm to 5.64 × 10−2 Ω.cm (K-doped) and 3.18 × 10−2 (Na-doped), respectively. Lastly, the carrier concentrations increased from 5.17 × 1017 (undoped ZnO) to 1 × 1018 (doped ZnO).

Ga-Sn Co-Doped ZnO Films via Sol-Gel Route

2018 ◽  
Vol 280 ◽  
pp. 43-49
Author(s):  
Zi Neng Ng ◽  
Kah Yoong Chan
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Band Gap ◽  
Doping Concentration ◽  
Sol Gel ◽  
Zno Films ◽  
Axis Orientation ◽  
Co Doping ◽  
Doped Zno ◽  
Co Doped

Zinc oxide (ZnO) has gained worldwide attention due to its direct wide band gap and large exciton binding energy, which are important properties in the application of emerging optoelectronic devices. By doping ZnO with donor elements, a combination of good n-type conductivity and good transparency in the visible and near UV range can be achieved. Co-doping ZnO with several types of dopants is also beneficial in improving the electronic properties of ZnO films. To the best of our knowledge, the fundamental properties of gallium-tin (Ga-Sn) co-doped ZnO (GSZO) films were rarely explored. In this work, we attempt to coat GSZO films on glass substrates via sol-gel spin-coating method. The Ga-Sn co-doping ratio was fixed at 1:1 and the concentration of the dopants was varied at 0.5, 1.0, 1.5, and 2 at.% with respect to the precursor. The AFM image show granular features on the morphology of all GSZO films. All samples also exhibit a preferential c-axis orientation as detected by XRD. The XRD indicates higher crystal quality and larger crystallite size on GSZO thin films at 2.0 at.% and agrees well with the AFM results. However, the transparency and optical band-gap of the GSZO thin films degrade with higher co-doping concentration. The best electrical properties were achieved at co-doping concentration of 1 at.% with conductivity and carrier density of 7.50 × 10-2S/cm and 1.37 × 1016cm-3, respectively. At 1.0 at.% co-doping concentration, optimal optical transmittance and electrical properties were achieved, making it promising in the application of optoelectronics.

Effects of SiO2 interlayer on electrical properties of Al-doped ZnO films under bending stress

2012 ◽  
Vol 8 (4) ◽  
pp. 375-379 ◽  
Author(s):  
Young Soo Lim ◽  
Seul Gi Seo ◽  
Bo Bae Kim ◽  
Hyoung-Seuk Choi ◽  
Won-Seon Seo ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Zno Films ◽  
Bending Stress ◽  
Doped Zno

On the UV-light-induced Desorption/Adsorption Mechanism of Atmospheric Species in Solution-processed Zinc Oxide Thin Films

MRS Advances ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 111-117
Author(s):  
José Bruno Cantuária ◽  
Giovani Gozzi ◽  
Lucas Fugikawa Santos
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Electrical Properties ◽  
Uv Light ◽  
Atmospheric Oxygen ◽  
Low Cost ◽  
Environmental Parameters ◽  
Zno Films ◽  
Desorption Rate ◽  
Transparent Semiconductor

AbstractZinc oxide (ZnO) is a n-type transparent semiconductor which can be processed by low cost techniques (such as spray-pyrolysis and spin-coating) and can be applied as the active layer of thin-films transistors (TFTs). The electrical properties of ZnO films are strongly affected when the device is exposed to room conditions and/or UV-light, suggesting possible applications as UV or/and gas sensors. Atmospheric oxygen molecules adsorbed on ZnO surface act as charge traps, decreasing the material conductivity. The incidence of UV-light causes an increase of the material conductivity due to the photogeneration of electron-hole pairs via direct band-to-band transitions (classic photoconductivity process) and due to the desorption of oxygen molecules, which presents a relatively slower response and is a less understood mechanism. In the current paper, we study the influence of environmental parameters, such as temperature, humidity and UV-light intensity, on the electrical properties of spin-coated ZnO thin films to understand the role of the desorption mechanism on the photoconductivity process. The analysis of the device current vs. time curves shows the existence of two light-induced desorption mechanisms: i) one which increases the electrical conductivity of the ZnO film (desorption-like process) and ii) a second one which decreases the conductivity (adsorption-like process). A Plackett-Burman design of experiment (DOE) was used to study the influence of characterization factors like UV intensity, temperature and humidity on electrical parameters obtained from the experimental curves. We observed that the desorption-like process is a first order mechanism, exhibiting desorption rate proportional to n(t), where n(t) represents the adsorbate concentration as a function of the time, whereas the adsorption-like mechanism exhibits a desorption rate proportional to the forth power of n(t).

Effect of Flexible Substrates on the Structural and Optical Properties of ZnO Films Deposited by Sputtering Method

2015 ◽  
Vol 1107 ◽  
pp. 678-683 ◽  
Author(s):  
Lam Mui Li ◽  
Azmizam Manie Mani ◽  
Saafie Salleh ◽  
Afishah Alias
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Low Cost ◽  
Argon Plasma ◽  
Optical Transmittance ◽  
Zno Thin Films ◽  
Plastic Substrate ◽  
Zno Films ◽  
X Ray Diffraction ◽  
X Ray

Zinc Oxide (ZnO) has attracted much attention because of its high optical transmittance approximately ~80 % with a wide band gap of (3.3 eV at 300 K) and a relatively low cost material. ZnO thin films were deposited on plastic substrate using RF powered magnetron sputtering method. The target used is ZnO disk with 99.99 % purity. The sputtering processes are carried out with argon gas that flow from 10-15 sccm. Argon is used to sputter the ZnO target because the ability of argon that can remove ZnO layer effectively by sputtering with argon plasma bombardment. The deposited ZnO thin films are characterized using X-Ray Diffraction (XRD) and UV-Vis Spectrometer. The analysis of X-ray diffraction show that good crystalline quality occurs at nominal thickness of 400 nm. The optical studies showed that all the thin films have high average transmittance of approximately 80 % and the estimated value of optical band gap is within 3.1 eV-3.3 eV range.

Structural, optical and magnetic properties of highly oriented transition metal (Mn/Co/Ni/Cu) doped ZnO thin films prepared by PLD

2012 ◽  
Vol 1454 ◽  
pp. 239-244 ◽  
Author(s):  
Arun Aravind ◽  
M.K. Jayaraj ◽  
Mukesh Kumar ◽  
Ramesh Chandra
Keyword(s):  
Thin Films ◽  
Transition Metal ◽  
Room Temperature Ferromagnetism ◽  
Visible Region ◽  
Band Edge ◽  
Zno Films ◽  
Band Edge Emission ◽  
Edge Emission ◽  
Axis Orientation ◽  
Doped Zno

ABSTRACTZnO doped with transition metal (TM) thin films were grown by pulsed laser deposition. XRD pattern reveals that all the ZnTMO films have c-axis orientation normal to the substrate. The reciprocal space mapping shows that the crystallinity of ZnTMO film deteriorates at higher doping of TM. All the TM doped ZnO films have transmittance greater than 75% in the visible region. The band gap of the ZnTMO thin films shows red shift on doping with Ni and Cu where as blue shift is observed for Co and Mn which increases with TM concentration. The copper doped ZnO thin film shows green PL emission at 542 nm along with the band edge emission at 385 nm. But other TM doping shows only band edge emission (385nm) and its intensity decreases at higher doping percentage. The presence of non-polar E2high and E2lowRaman modes in thin films indicates that ‘TM’ doping do not alter the wurtzite structure of ZnO. The magnetic studies of the TM doped ZnO shows room temperature ferromagnetism

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