Structural, spectroscopic and electrical properties of dc magnetron sputtered NiO thin films and an insight into different defect states

Abstract

In this article, we report a detailed study on the influence of sputter power on physical properties of the NiO films grown by DC magnetron sputtering. Structural studies carried out by Grazing Incidence X-ray diffraction (XRD) reveals the polycrystalline nature of the films with FCC phase. The crystallographic orientation (111) plane followed by (200), (220), and (311) plane were evident from the XRD spectra. The average crystallites sizes were estimated from the spectra, and the values were compared using three different plots such as Scherrer, Williamson–Hall and size–strain plot. The surface morphology was carried out by atomic force microscopy. The deposited samples show semitransparent behavior in the visible region and the estimated band gap increased from 2.70 to 3.34 eV with an increase in sputter power. Furthermore, X-ray photoelectron spectroscopy (XPS) core-level Ni2p spectra were deconvoluted and the observed $${\text{Ni}}2{\text{p}}_{{{\text{3/2}}}}$$ Ni 2 p 3/2 , $${\text{Ni}}2{\text{p}}_{{1/2}}$$ Ni 2 p 1 / 2 domain along with their satellite’s peaks were analyzed. Most importantly, XPS quantification data and Raman spectra confirm the presence of both $${\rm{Ni}}^{2+}$$ Ni 2 + and $${\rm{Ni}}^{3+}$$ Ni 3 + states in the NiO films. The electrical properties carried at room temperature revealed that the resistivity of the film significantly increased and a mobility of ~ 84 $${\rm{cm}}^{2}{\rm{V}}^{-1}{s}^{-1}$$ cm 2 V - 1 s - 1 was obtained.

Effect of oxidation temperature on the properties of NiOx layers for application in optical sensors

“…Higher temperature provides more thermal energy, which favors formation of larger grains with improved crystallinity [28,30] 3+ have been reported in Ref. [32]. The Ni 2p 3/2 region in Fig.…”

“…The first peak at 853.4, 853.0, and 853.1 eV, for samples oxidized at 400, 500 and 600 °C, respectively, corresponds to Ni 2+ in NiO [33,34]. The second one at 855.1, 854.7, and 855.0 eV, for oxidation temperature of 400, 500 and 600 °C, contains contributions of Ni 2+ and Ni 3+ states in NiO and Ni 2 O 3 , respectively, [25,31,32] as well as of NiOOH and Ni(OH) 2 [9]. The O 1s region was fitted with two peaks related to NiO and Ni 2 O 3 , respectively.…”

Nickel Oxide Films Deposited by Sol-Gel Method: Effect of Annealing Temperature on Structural, Optical, and Electrical Properties

“…NiO is a transition metal oxide, and it is important to know the oxidation states. NiO exhibits spin–orbit doublet and its multiple peaks result in a complicated line shape, peak asymmetries, complex multiplet splitting, shake-up, plasmon loss structure, and overlapping binding energies, and it is difficult to determine the proportion of different Ni valences [ 38 , 39 ]. Figure 3 presents the XPS spectra of Ni 2p, O 1s, and C 1s core levels and their fitted results using Gaussian curves after the subtraction of a Shirley baseline.…”

“…The O 1s spectrum revealed two definite lines. The first main peak is at the binding energy of 529.5 eV, due to metal-oxygen (O-Ni 2+ ) bonds [ 46 ], and it is referred to as almost pure stoichiometric NiO [ 38 ]. The other peak, at BE = 531.3 eV, has been attributed to the formation of Ni 2 O 3 (O -Ni 3+ ) by many authors [ 41 , 44 , 46 ] (the corresponding Ni 2p3/2 peak at 855.7 eV is detected as can be observed in Figure 3 c, but this can be disputed as it is also associated with adsorption of different oxygen-containing species such as Ni(OH) 2 and NIO(OH), and defects in NiO [ 47 , 48 ]).…”

Electrochemical behavior of spray deposited nickel oxide (NiO) thin film in Alkaline electrolyte

“…Various methods were used to prepare NiO thin layers, such as chemical vapor deposition (CVD) [17], atomic layer deposition (ALD) [18], dc-magnetron sputtering [19], pulsed laser deposition (PLD) [20], electron-beam evaporation [21], spray pyrolysis [22], sol-gel process [23], chemical bath deposition (CBD) [24] and the electrodeposition process etc. [1], [25].…”