“…Direct relation of this parameter with three factors of absorption edge, donor carrier concentration, and impurity energy levels has been known. Shift of absorption edge to lower energies and consequently decreasing the band gap is due to decrease in impurity energy levels 47 . Figure 7 dT/dλ of NiO thin films on quartz substrate with different annealing temperatures.…”
Section: Resultsmentioning
confidence: 99%
“…Applying the well-known Tauc relation in the appendix S1 (Part A), which has been described by Ilkhani, et al 47 in details and considering indirect allowed transition accordingly, the optical bandgap values of the NiO thin films were calculated (Fig. 9 ).…”
Due to the large number of industrial applications of transparent conductive oxides (TCOs), this study focuses on one of the most important metal oxides. The RF-magnetron sputtering method was used to fabricate NiO thin films on both quartz and silicon substrates at room temperature under flow of Argon and Oxygen. The sputtered samples were annealed in N2 atmosphere at 400, 500, and 600 °C for 2 hours. Using the AFM micrographs and WSXM 4.0 software, the basic surface parameters, including root mean square roughness, average roughness, kurtosis, skewness, etc., were computed. Advanced surface parameters were obtained by the Shannon entropy through a developed algorithm, and the power spectral density and fractal succolarity were extracted by related methods. Optical properties were studied using a transmittance spectrum to achieve the optical bandgap, absorption coefficient, Urbach energy, and other optical parameters. Photoluminescence properties also showed interesting results in accordance with optical properties. Finally, electrical characterizations and I–V measurements of the NiO/Si heterojunction device demonstrated that it can be used as a good diode device.
“…Direct relation of this parameter with three factors of absorption edge, donor carrier concentration, and impurity energy levels has been known. Shift of absorption edge to lower energies and consequently decreasing the band gap is due to decrease in impurity energy levels 47 . Figure 7 dT/dλ of NiO thin films on quartz substrate with different annealing temperatures.…”
Section: Resultsmentioning
confidence: 99%
“…Applying the well-known Tauc relation in the appendix S1 (Part A), which has been described by Ilkhani, et al 47 in details and considering indirect allowed transition accordingly, the optical bandgap values of the NiO thin films were calculated (Fig. 9 ).…”
Due to the large number of industrial applications of transparent conductive oxides (TCOs), this study focuses on one of the most important metal oxides. The RF-magnetron sputtering method was used to fabricate NiO thin films on both quartz and silicon substrates at room temperature under flow of Argon and Oxygen. The sputtered samples were annealed in N2 atmosphere at 400, 500, and 600 °C for 2 hours. Using the AFM micrographs and WSXM 4.0 software, the basic surface parameters, including root mean square roughness, average roughness, kurtosis, skewness, etc., were computed. Advanced surface parameters were obtained by the Shannon entropy through a developed algorithm, and the power spectral density and fractal succolarity were extracted by related methods. Optical properties were studied using a transmittance spectrum to achieve the optical bandgap, absorption coefficient, Urbach energy, and other optical parameters. Photoluminescence properties also showed interesting results in accordance with optical properties. Finally, electrical characterizations and I–V measurements of the NiO/Si heterojunction device demonstrated that it can be used as a good diode device.
“…Thermal annealing is one of the effective ways to control surface modification by controlling the dimensions and overall morphology of the nanostructure. Apart from this fundamental aspect, nowadays, dilute magnetic semiconductors have attracted the attention of the research fraternity for fabricating spintronic devices owing to their capability to control charging and rotation simultaneously [17,18]. With high transparency and better optoelectronic properties of ZnO, it further indicates a potential candidature with transition metal (TM) doping to devise a transparent magnetic device [19].…”
This study thoroughly examines the collective influence of compositional variation and annealing temperature on the electronic structure of sol–gel derived NixZn1−xO (x = 0 to 1) thin films annealed at different temperatures (700
°
C, 800
°
C, and 900
°
C) using x-ray photoelectron spectroscopy (XPS) and x-ray absorption spectroscopy. A gradual structural phase transition from hexagonal wurtzite ZnO to cubic rocksalt NiO with increasing Ni concentration was revealed by x-ray diffraction (XRD). Grain growth was observed from scanning electron microscopy with increasing annealing temperature. Photoluminescence measurements indicate the presence of interstitial oxygen when Ni atoms are incorporated in the film. The Ni L
3,2 absorption edge shows an intensity enhancement in the white-line feature with increasing Ni concentration, evidencing the presence of higher oxidation states. Concurring results were observed by XPS where both Ni2+ and Ni3+ free ion multiplets are present in the Ni 2p core level spectrum for 20% and higher Ni concentration. O K and Zn L
3,2 XAS spectra demonstrated the e
g-t
2g sub-band splitting at higher Ni concentration, triggered by band anti-crossing interaction and crystal field splitting. The extended x-ray absorption fine structure (EXAFS) simulation for the Zn K edge revealed a Zn–Zn/Ni bond length change for 60% Ni concentration. The thermal disorder factor increased up to 40% Ni concentration, and beyond that, it decreased due to stable NiO phase dominance in the alloy composite. Ni K edge EXAFS fitting indicated an insignificant change in the Ni-O and Ni–Ni/Zn bond lengths throughout the range of varying Ni concentrations. The thermal disorder factor increases with increasing annealing temperature, indicating a more disordered lattice. Such investigation is essential where the electronic properties of nanometer-sized materials determine the performance of functional devices. The present work critically elucidates the combined impact of compositional variations and annealing temperatures on electronic structures.
“…Because of high sensitivity of pure ZnO thin films to the oxidation and also its high transmittance in the visible area, ZnO thin films were doped with aluminum initially. Then, all samples were annealed in order to decrease resistivity and increase band gap energy, carrier concentration, and stability [6]. On the other hand, Al:ZnO (AZO) is a promising material for light emitting diodes, solar cells, and gas sensors along with general optoelectronic applications [7][8].…”
The aim of the present study is to verify the effect of annealing temperature variation on zinc oxide doped with aluminum (AZO) thin films deposited on p-type silicon (Si) substrates. Here, AZO/p-Si heterojunction was annealed in nitrogen environment and its structural, electrical, and optical characterizations were investigated. The results of XRD patterns showed the amorphous structure of AZO thin films. FE-SEM images illustrated the increase of grain size by increasing annealing temperature up to 500 o C. The reflectance analysis showed that for this annealing temperature, that the energy band gap of AZO thin film was moved to higher energy level. The electrical properties were investigated by I-V measurement carried out in the light at room temperatures. The short circuit current (I SC ), ideality factor, saturation current, and open circuit voltage (V OC ) of the AZO/p-Si heterojunction strongly depended on annealing conditions due to charge carrier trapping and density of defect on interface. By considering I R and I F as reverse and forward current, the ration of I F /I R had the maximum value at 1 V which was belonged to n-AZO/p-Si heterojunction at 500 o C annealing temperature.
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