Raman spectroscopy of V and Co doped ZnO ceramics and thin films

2004 ◽  
Vol 829 ◽  
Author(s):  
K. Samanta ◽  
N. Awasthi ◽  
B. Sundarakannan ◽  
P. Bhattacharya ◽  
R. S. Katiyar
Keyword(s):  
Thin Films ◽  
Raman Spectra ◽  
Processing Route ◽  
Secondary Phases ◽  
Axis Orientation ◽  
Co Doping ◽  
Electronic Raman Scattering ◽  
Doped Zno ◽  
Integrated Intensities ◽  
Co Doped

ABSTRACTLattice dynamical and electronic transition changes due to V and Co doped ZnO have been investigated using optical techniques. Vanadium and Co doped ZnO pellets were prepared using conventional ceramic processing route and thin films were fabricated by pulsed laser deposition. Raman spectra of Zn1-xVxO targets showed many additional peaks in the range of 230 to 350 cm-1 and 750 to 900 cm-1. Integrated intensities of these additional modes decreased with increase of temperature as similar to the host ZnO modes, which precludes electronic Raman scattering to be the origin. Raman peaks for stoichiometric Zn3(VO4)2 and Zn2V2O7 compounds also had additional peaks that can be attributed to the secondary phases formed in the compositions of Zn1-xVxO. Raman spectra of Zn1-xCoxO showed no additional modes besides ZnO modes, however, the intensity of the second order peak at 540 cm-1 was increased due to Co doping. Thin films of Zn1-xCoxO exhibited highly c-axis orientation deposited on (001)Al2O3 substrates. The optical absorption of the films showed that the band gap decreased with increase of Co concentrations at room temperature along with the sub bandgap absorptions due to d-d transitions of Co2+.

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.

Transport mechanisms in Co-doped ZnO (ZCO) and H-irradiated ZCO polycrystalline thin films

2021 ◽  
Vol 23 (3) ◽  
pp. 2368-2376
Author(s):  
A. Di Trolio ◽  
A. Amore Bonapasta ◽  
C. Barone ◽  
A. Leo ◽  
G. Carapella ◽  
...  
Keyword(s):  
Thin Films ◽  
Opposite Effect ◽  
Transport Mechanisms ◽  
Co Doping ◽  
Polycrystalline Thin Films ◽  
Doped Zno ◽  
Co Doped

Co doping increases the ZnO resistivity (ρ) at high T (HT), whereas it has an opposite effect at low T (LT). H balances the Co effects by neutralizing the ρ increase at HT and strengthening its decrease at LT.

scholarly journals Fabrication of Ag and Mn Co-Doped Cu2ZnSnS4 Thin Film

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1520
Author(s):  
Lei Qiu ◽  
Jiaxiong Xu ◽  
Xiao Tian
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Sol Gel ◽  
Experimental Results ◽  
Nonradiative Recombination ◽  
Secondary Phases ◽  
Co Doping ◽  
Enhanced Photoluminescence ◽  
Cu2znsns4 Thin Film ◽  
Co Doped

Ag and Mn dopants were incorporated into Cu2ZnSnS4 thin film to reduce defects in thin film and improve thin film properties. Sol–gel and spin-coating techniques were employed to deposit Ag and Mn co-doped Cu2ZnSnS4 thin films. The structures, compositions, morphologies, and optical properties of the co-doped thin films were characterized. The experimental results indicate the formation of kesterite structure without Ag and Mn secondary phases. The amount of Ag in the thin films is close to that in the sols. The co-doped Cu2ZnSnS4 thin films have an absorption coefficient of larger than 1.3 × 104 cm−1, a direct optical band gap of 1.54–2.14 eV, and enhanced photoluminescence. The nonradiative recombination in Cu2ZnSnS4 thin film is reduced by Ag and Mn co-doping. The experimental results show that Ag and Mn incorporation can improve the properties of Cu2ZnSnS4 thin film.

scholarly journals Enhanced Electrical Properties and Stability of P-Type Conduction in ZnO Transparent Semiconductor Thin Films by Co-Doping Ga and N

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1069
Author(s):  
Chien-Yie Tsay ◽  
Wan-Yu Chiu
Keyword(s):  
Thin Films ◽  
Hole Concentration ◽  
Sol Gel ◽  
Co Doping ◽  
Semiconductor Thin Films ◽  
Doped Zno ◽  
Transparent Semiconductor ◽  
P Type ◽  
Type Conduction ◽  
Co Doped

P-type ZnO transparent semiconductor thin films were prepared on glass substrates by the sol-gel spin-coating process with N doping and Ga–N co-doping. Comparative studies of the microstructural features, optical properties, and electrical characteristics of ZnO, N-doped ZnO (ZnO:N), and Ga–N co-doped ZnO (ZnO:Ga–N) thin films are reported in this paper. Each as-coated sol-gel film was preheated at 300 °C for 10 min in air and then annealed at 500 °C for 1 h in oxygen ambient. X-ray diffraction (XRD) examination confirmed that these ZnO-based thin films had a polycrystalline nature and an entirely wurtzite structure. The incorporation of N and Ga–N into ZnO thin films obviously refined the microstructures, reduced surface roughness, and enhanced the transparency in the visible range. X-ray photoelectron spectroscopy (XPS) analysis confirmed the incorporation of N and Ga–N into the ZnO:N and ZnO:Ga–N thin films, respectively. The room temperature PL spectra exhibited a prominent peak and a broad band, which corresponded to the near-band edge emission and deep-level emission. Hall measurement revealed that the ZnO semiconductor thin films were converted from n-type to p-type after incorporation of N into ZnO nanocrystals, and they had a mean hole concentration of 1.83 × 1015 cm−3 and a mean resistivity of 385.4 Ω·cm. In addition, the Ga–N co-doped ZnO thin film showed good p-type conductivity with a hole concentration approaching 4.0 × 1017 cm−3 and a low resistivity of 5.09 Ω·cm. The Ga–N co-doped thin films showed relatively stable p-type conduction (>three weeks) compared with the N-doped thin films.

Co-doping Deposition of p-type ZnO Thin Films using KrF Excimer Laser Ablation

2002 ◽  
Vol 747 ◽  
Author(s):  
Kenji Ebihara ◽  
Tamiko Ohshima ◽  
Tomoaki Ikegami ◽  
Jes Asumussen ◽  
Raj K. Thareja
Keyword(s):  
Thin Films ◽  
Zno Thin Films ◽  
Zno Films ◽  
Axis Orientation ◽  
Excimer Laser Ablation ◽  
Co Doping ◽  
Doped Zno ◽  
Krf Excimer Laser ◽  
P Type ◽  
Nitrogenous Gases

ABSTRACTWe report on the attempt to fabricate p-type ZnO thin films using various doping techniques based on the pulsed laser deposition (PLD). As an accepter, we have doped the N atom by using high purity nitric monoxide (NO) ambient gas. NO is dissociated into N and O at an energy of 6.5 eV which is lower than at N2 (9.76 eV). Moreover the dissociation reaction of NO is simpler than other nitrogenous gases such as N2O, NO2, and NH3. One of our doping techniques is co-doping of Ga and N atom by ablating ZnO:Ga target in NO gas, and another is the ablation of the metal Zn target in NO gas. Both of Ga and N co-doped ZnO films and N doped ZnO films have c-axis orientation as well as undoped ZnO films. The surfaces of these doped films are rough while the undoped ZnO thin film is very smooth and have hexagonally shaped grains. We found it possible to fabricate the p-type ZnO film by ablating the metal Zn target in NO gas.

Influence of Substrate Rotational Speed on the Structural and Optical Properties of Sputtered Gd-Doped ZnO Thin Films

2021 ◽  
Vol 1023 ◽  
pp. 3-8
Author(s):  
Nur Amaliyana Raship ◽  
Siti Nooraya Mohd Tawil ◽  
Nafarizal Nayan ◽  
Khadijah Ismail ◽  
Anis Suhaili Bakri ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Rotation Speed ◽  
Surface Topology ◽  
Zno Thin Films ◽  
Secondary Phases ◽  
Structural And Optical Properties ◽  
Axis Orientation ◽  
Substrate Rotation ◽  
Doped Zno

Rare-earth element of gadolinium (Gd) were successfully doped into zinc oxide (ZnO) using dual sputter source of DC and RF sputtering. The substrate rotation speed was controlled from 1 rpm to 9 rpm to investigate their effects on the properties of the films in order to achieve a great feature of thin film. XRD profiles confirmed the c-axis orientation with structure of ZnO hexagonal wurtzite. No peaks related to secondary phases were observed. The intensity of dominant peak showed increment upon improvement of substrate rotation speed. The incorporation of Gd into ZnO structure was further confirmed by composition element form EDX with average atomic percentage of 3 at. % for all the films. Surface topology from AFM images showed the grain size has increased with the higher speed of substrate rotation. Gd-doped ZnO thin films indicated good transparency with an average transmittance above 90 % regardless of substrate rotation speed. The bandgap has a slight decrease from 3.06 eV to 3.03 eV with an increment speed of rotational substrate. These findings further imply that the substrate rotation speed has a significant influence on the structural and optical properties of the sputtered thin films.

Influence of N Dopant on the Electric and Magnetic Properties of Co Doped ZnO Thin Films

2010 ◽  
Vol 25 (7) ◽  
pp. 711-716 ◽  
Author(s):  
Xue-Tao WANG ◽  
Li-Ping ZHU ◽  
Zhi-Gao YE ◽  
Zhi-Zhen YE ◽  
Bing-Hui ZHAO
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Zno Thin Films ◽  
Doped Zno ◽  
Co Doped

Photoluminescence and Magnetic Properties of Undoped and (Mn, Co) co-doped ZnO Nanoparticles

2020 ◽  
Vol 16 (4) ◽  
pp. 655-666
Author(s):  
Mona Rekaby
Keyword(s):  
Magnetic Properties ◽  
Zno Nanoparticles ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Structural Defects ◽  
Ferromagnetic Behavior ◽  
Secondary Phases ◽  
Antiferromagnetic Ordering ◽  
Doped Zno ◽  
Co Doped

Objective: The influence of Manganese (Mn2+) and Cobalt (Co2+) ions doping on the optical and magnetic properties of ZnO nanoparticles was studied. Methods: Nanoparticle samples of type ZnO, Zn0.97Mn0.03O, Zn0.96Mn0.03Co0.01O, Zn0.95Mn0.03 Co0.02O, Zn0.93Mn0.03Co0.04O, and Zn0.91Mn0.03Co0.06O were synthesized using the wet chemical coprecipitation method. Results: X-ray powder diffraction (XRD) patterns revealed that the prepared samples exhibited a single phase of hexagonal wurtzite structure without any existence of secondary phases. Transmission electron microscope (TEM) images clarified that Co doping at high concentrations has the ability to alter the morphologies of the samples from spherical shaped nanoparticles (NPS) to nanorods (NRs) shaped particles. The different vibrational modes of the prepared samples were analyzed through Fourier transform infrared (FTIR) measurements. The optical characteristics and structural defects of the samples were studied through Photoluminescence (PL) spectroscopy. PL results clarified that Mn2+ and Co2+ doping quenched the recombination of electron-hole pairs and enhanced the number of point defects relative to the undoped ZnO sample. Magnetic measurements were carried out at room temperature using a vibrating sample magnetometer (VSM). (Mn, Co) co-doped ZnO samples exhibited a ferromagnetic behavior coupled with paramagnetic and weak diamagnetic contributions. Conclusion: Mn2+ and Co2+ doping enhanced the room temperature Ferromagnetic (RTFM) behavior of ZnO. In addition, the signature for antiferromagnetic ordering between the Co ions was revealed. Moreover, a strong correlation between the magnetic and optical behavior of the (Mn, Co) co-doped ZnO was analyzed.

scholarly journals Photo-activity and low resistivity in N/Nb Co-doped TiO2 thin films by combinatorial AACVD

2016 ◽  
Vol 4 (2) ◽  
pp. 407-415 ◽  
Author(s):  
Nicholas P. Chadwick ◽  
Emily N. K. Glover ◽  
Sanjayan Sathasivam ◽  
Sulaiman N. Basahel ◽  
Shaeel A. Althabaiti ◽  
...  
Keyword(s):  
Thin Films ◽  
Functional Properties ◽  
Tio2 Thin Films ◽  
Doped Tio2 ◽  
Low Resistivity ◽  
Co Doping ◽  
Co Doped

Combinatorial AACVD has achieved the production of various niobium/nitrogen co-doped TiO2 materials in a single film. The co-doping concentrations have been correlated with functional properties.

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