Effect of film thickness on properties of aluminum doped zinc oxide thin films deposition on polymer substrate

A series of aluminum doped zinc oxide thin films with different thickness (25–150 nm) were deposited on indium tin oxide coated polyethylene terephthalate substrates by radio frequency magnetron sputtering method at room temperature. The structural, optical and electrical properties of the films were investigated by X-ray Diffractometer, UV–Vis spectrometer and Hall Effect Measurement System. All the obtained films were polycrystalline with a hexagonal structure and a preferred orientation along [002] direction with the c-axis perpendicular to the substrate surface. The optical energy band gap (E_g) values of the films were found to be in the range from 3.36 to 3.26 eV, and their average optical transmissions were about 75 % in the visible region. The films had excellent electrical properties with the resistivities in the range from 2.78 × 10^?5 to 2.03 × 10^?4 Ω cm, carrier densities more than 3.35 × 10²¹ cm^?3 and Hall mobilities between 5.77 and 11.13 cm²/V s.     

Photoelectrochemical studies on spray deposited copper selenide thin films

Thin films of copper selenide have been deposited by spraying a mixture of aqueous solutions (0.50 M) of copper chloride hydrate (CuCl₂·2H₂O) and selenourea [H₂NC(Se)NH₂] on preheated fluorine doped tin oxide coated glass substrates at various substrate temperatures. The cell configurations copper selenide/0.5 M K₂SO₄/C are used for studying the capacitance–voltage (C–V) characteristics in the dark, current–voltage (I–V) characteristics in dark and under illumination, photovoltaic power output and spectral response characteristics of the as deposited films. Photoelectrochemical study records that as deposited copper selenide thin films are of p-type. The spectral response characteristics of the films at room temperature show a prominent, sharp peak at 550 nm. The measured values of efficiency (η) and fill factor (FF) are found to be 0.99 % and 0.51 respectively for film deposited at 350 °C.     

Effect of very low to high Sb-doping on the structural,electrical, photo-conductive and thermoelectric properties of fluorine-doped SnO<Subscript>2</Subscript> (FTO) thin films prepared by spray pyrolysis technique

Transparent conducting fluorine and Sb-doped [SnO₂: (F, Sb)] thin films have been deposited onto preheated glass substrates using the spray pyrolysis technique by the various dopant quantity of spray solution. The effect of antimony impurities on the structural, morphological, electrical, Thermo-electrical, optical and photoconductive properties of films has been investigated. The [F/Sn] atomic concentration ratio (x) in the spray solution is kept at value of 0.7 and the [Sb/Sn] atomic ratio (y) varied at values of 0, 0.0005, 0.001, 0.002, 0.01, 0.03, 0.05, 0.07 and 0.10. It is found that the films are polycrystalline in nature with a tetragonal crystal structure corresponding to SnO₂ phase having orientation along the (110) and (200) planes. SEM images indicated that nanostructure of the films has a particle type growth. The average grain size increases with increasing spraying quantity of Sb-dopant. The compositional analysis of SnO₂: (F, Sb) thin films were studied using EDAX. SEM and AFM study reveals the surface of SnO₂: (F, Sb) to be made of nanocrystalline particles. The Hall Effect measurements have shown n-type conductivity in all deposited films. The lowest sheet resistance and highest the carrier concentration about 7.7 Ω/□ and 6.6 × 10²², respectively, were obtained for the film deposited with y = [Sb/Sn] = 0.001 and x = [F/Sn] = 0.7. The maximum of the Seebeck coefficient equal to 12.8 μV K^?1 was obtained at 400 K for the film deposited with y = [Sb/Sn] = 0.10. The average transmittance of films varied over the range 10–80 % with change of Sb-concentration. The band gap values of samples were obtained in the range of 3.19–3.8 eV. From the photoconductive studies, the Sb-doped films exhibited sensitivity to incident light especially in y = 0.001. The electrical resistivity and carrier concentration vary in range 5.44 × 10^?4 to 1.02 × 10^?2Ω cm and 2.6 × 10²²–6.6 × 10²² cm^?3, respectively.     

Band gap engineering in PbSe thin films from near-infrared to visible region by photochemical deposition method

Lead selenide (PbSe) thin films have been synthesized by the established photochemical deposition technique using lead nitrate and lead acetate as sources for the metal ions and sodium seleno sulphate as the selenium source along with triethanolamine, ammonia and hydrazine hydrate as complexing agents. A comprehensive study of the effect of substrate materials on physical properties of as deposited PbSe thin films is reported in this work. Two substrates were used in this investigation, namely soda lime glass slides and gold coin corning glass slides. The solution is irradiated with UV light and the photochemical reactions in the aqueous solution resulted in highly adherent metallic thin films. X-ray diffraction (XRD), scanning electron microscopy, optical and electrical measurement techniques were used for film characterization. The XRD analysis confirmed that all films were cubic, regardless of the cationic precursors and substrates used. The scanning electron microscope micrographs showed variations in morphology. The optical studies revealed that the films have good absorption in the visible region. The remarkable success of our effort was that we have been able to modify optical band gap of PbSe thin films over a wide spectral range by a cost effective route. The band gaps estimated from the transmission spectra were in the range 1.32–1.40 eV for films deposited on soda lime glass substrates and 1.46–1.55 eV for corning glass substrates. The room temperature conductivity of the PbSe films were in the range of 3.71 × 10^?7–513 × 10^?7 (Ω cm)^?1. The as deposited PbSe thin films with low transmittance in the visible region coupled with an appreciable reflectance in infrared region were found to satisfy the basic requirements for solar control coatings for window glazing applications in warm climates. Through this work we established that irrespective of metal salts, soda lime glass substrate was superior to corning glass substrate.     

Effect of substrate temperature on the structural,morphological and optical properties of copper bismuth sulfide thin films deposited by electron beam evaporation method

Copper bismuth sulfide thin films were deposited at 200 °C, 300 °C, 400 °C and 500 °C on the glass substrates by electron beam evaporation method. X-ray diffraction study revealed that the copper bismuth sulfide films of single and mixed phases were formed as a function of substrate temperatures. Substrate temperature of 300 °C and 400 °C formed single phase Cu₄Bi₄S₉ and Cu₄Bi₅S₁₀ films respectively whereas substrate temperature of 500 °C formed mixed phases of Cu₄Bi₄S₉ and Cu₄Bi₅S₁₀ film. Crystallite size, dislocation density and microstrain of the films were modified by the various substrate temperatures. Surface morphology of the film Cu₄Bi₅S₁₀ deposited at 400 °C examined by scanning electron microscopy showed the distribution of spherical shaped particles on the film surface. The presence of copper, bismuth and sulfur elements in the deposited films was confirmed using energy dispersive spectral studies. The calculated direct optical band gap energy of the films deposited at different substrate temperature varied from 1.47 to 1.64 eV and the absorption coefficient is in the order of 10⁶ cm^?1.     

Effects of growth temperature on electrical and structural properties of sputtered GaN films with a cermet target

GaN films have been deposited at 100–400 °C substrate temperature on Si (100) and sapphire (0001) substrates by RF reactive sputtering in an (Ar + N₂) atmosphere. A (Ga + GaN) cermet target for sputtering was made by hot pressing the mixed powders of metallic Ga and ceramic GaN. The effects of substrate temperature on the GaN formation and its properties were investigated. The diffraction results showed that GaN films with a preferential (10–10) growth plane had a wurtzite crystalline structure. GaN films became smoother at higher substrate temperature. The Hall effect measurements showed the electron concentration and mobility were 1.04 × 10¹⁸ cm^?3 and 7.1 cm² V^?1 s^?1, respectively, for GaN deposited at 400 °C. GaN films were tested for its thermal stability at 900 °C in the N₂ atmosphere. Electrical properties slightly degraded after annealing. The smaller bandgap of ~3.0 eV is explained in terms of intrinsic defects and lattice distortion.     

Effect of annealing time on the structural,optical and electrical characteristics of DC sputtered ITO thin films

Using an Indium tin oxide (ITO) ceramic target (In₂O₃:SnO₂, 90:10 wt%), ITO thin films were deposited by conventional direct current magnetron sputtering technique onto glass substrates at room temperature. The obtained ITO films were annealed at 400 °C for different annealing times (1, 2, 5, 7, and 9 h). The effect of annealing time on their structural, optical and electrical properties was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microcopy (AFM), ultra violet–visible (UV–Vis) spectrometer, and temperature dependence Hall measurements. XRD data of obtained ITO films reveal that the films were polycrystalline with cubic structure and exhibit (222), (400) and (440) crystallographic planes of In₂O₃. AFM and Scanning Electron Microscopy SEM have been used to probe the surface roughness and the morphology of the films. The refractive index (n), thickness and porosity (%) of the films were evaluated from transmittance spectra obtained in the range 350–700 nm by UV–Vis. The optical band gap of ITO film was found to be varying from 3.35 to 3.47 eV with the annealing time. The annealing time dependence of resistivity, carrier concentration, carrier mobility, sheet resistance, and figure of merit values of the films at room temperature were discussed. The carrier concentration of the films increased from 1.21 × 10²⁰ to 1.90 × 10²⁰ cm^?3, the Hall mobility increased from 11.38 to 18 cm² V^?1 s^?1 and electrical resistivity decreased from 3.97 × 10^?3 to 2.13 × 10^?3 Ω cm with the increase of annealing time from 1 to 9 h. Additionally, the temperature dependence of the carrier concentration, and carrier mobility for the as-deposited and 400 °C annealed ITO films for 2 and 9 h were analysed in the temperature range of 80–350 K.     

Properties of pulse electrodeposited copper indium selenide films

Copper Indium Selenide films were deposited by the pulse plating technique at different bath temperatures in the range of 30–80 °C and at 50 % duty cycle (15 s ON and 15 s OFF). X-ray diffraction studies indicated the formation of single phase chalcopyrite copper indium selenide films. The band gap of the films decreased from 1.17 to 1.05 eV with decrease of duty cycle. Atomic force microscope studies indicated that the surface roughness and grain size increased with duty cycle. Room temperature resistivity of the films is in the range of 0.01–2.0 ohm cm. Films deposited at 50 % duty cycle have exhibited a V_oc of 0.59 V, J_sc of 15 mA cm^?2, FF of 0.75 and efficiency of 6.64 %.     

Low indium content In–Zn–O system towards transparent conductive films: structure,properties and comparison with AZO and GZO

In this work, low content indium doped zinc oxide (IZO) thin films were deposited on glass substrates by RF magnetron sputtering using IZO ceramic targets with the In₂O₃ doping content of 2, 6, and 10 wt%, respectively. The influences of In₂O₃ doping content and substrate temperature on the structure and morphology, electrical and optical properties, and environmental stability of IZO thin films were investigated. It was found that the 6 wt% doped IZO thin film deposited at 150?°C exhibited the best crystal quality and the lowest resistivity of 9.87?×?10^?4 Ω cm. The corresponding Hall mobility and carrier densities were 9.20 cm² V^?1 s^?1 and 6.90?×?10²⁰ cm^?3, respectively. Compared with 2 wt% Al₂O₃ doped ZnO and 5 wt% Ga₂O₃ doped ZnO thin films, IZO thin film with the In₂O₃ doping content of 6 wt% featured the lowest surface roughness of 1.3 nm. It also showed the smallest degradation with the sheet resistance increased only about 4.4% at a temperature of 121?°C, a relative humidity of 97% for 30 h. IZO thin film with 6 wt% In₂O₃ doping also showed the smallest deterioration with the sheet resistance increased only about 2.8 times after heating at 500?°C for 30 min in air. The results suggested that low indium content doped ZnO thin films might meet practical requirement in environmental stability needed optoelectronic devices.     

Growth and characterizations of dual ion beam sputtered CIGS thin films for photovoltaic applications

The growth of CIGS thin films on soda-lime glass substrates at different substrate temperatures by dual ion beam sputtering system in a single-step route from a single quaternary sputtering target with the composition of Cu (In_0.70 Ga_0.30) Se₂ was reported. The effects of the substrate temperature on structural, optical, morphological and electrical properties of CIGS films were investigated. Stoichiometry of one such film was investigated by X-ray photoelectron spectroscopy. All CIGS films had demonstrated a strong (112) orientation located at 2θ ~26.70^o, which indicated the chalcopyrite structure of films. The value of full-width at half-maximum of (112) peak was reduced from 0.58° to 0.19° and crystallite size was enlarged from 14.98 to 43.05 nm as growth temperature was increased from 100 to 400 °C. However, atomic force microscope results showed a smooth and uniform surface at lower growth temperature and the surface roughness was observed to increase with increasing growth temperature. Hall measurements exhibited the minimum film resistivity of 0.09 Ω cm with a hole concentration of 2.42 × 10¹⁸ cm^?3 and mobility of 28.60 cm² V^?1 s^?1 for CIGS film grown at 100 °C. Film absorption coefficient was found to enhance nominally from 1 × 10⁵ to 2.3 × 10⁵ cm^?1 with increasing growth temperature from 100 to 400 °C.     

Brush plated copper indium sulphide films and their properties

Copper indium sulphide films were deposited for the first time by the brush plating technique at different electrolyte temperatures in the range of 30–80 °C and at a constant deposition current density of 5.0 mA cm^?2. The Films exhibited single phase copper indium sulphide. The grain size increased with increase of electrolyte temperature. Optical band gap of the films varied in the range of 1.30–1.42 eV. Atomic force microscopy studies indicated that the grain size vary from 600 to 1,000 nm, with increase of substrate temperature. Solar cells fabricated with the films exhibited V_oc of 650 mV, J_sc of 19.5 mA cm^?2, ff of 0.73 and efficiency of 9.50 %.     

Carrier properties of B atomic-layer-doped Si films grown by ECR Ar plasma-enhanced CVD without substrate heating

Abstract

The atomic-layer (AL) doping technique in epitaxy has attracted attention as a low-resistive ultrathin semiconductor film as well as a two-dimensional (2-D) carrier transport system. In this paper, we report carrier properties for B AL-doped Si films with suppressed thermal diffusion. B AL-doped Si films were formed on Si(100) by B AL formation followed by Si cap layer deposition in low-energy Ar plasma-enhanced chemical-vapor deposition without substrate heating. After fabrication of Hall-effect devices with the B AL-doped Si films on unstrained and 0.8%-tensile-strained Si(100)-on-insulator substrates (maximum process temperature 350°C), carrier properties were electrically measured at room temperature. Typically for the initial B amount of 2?×?10¹⁴ cm^?2 and 7?×?10¹⁴ cm^?2, B concentration depth profiles showed a clear decay slope as steep as 1.3 nm/decade. Dominant carrier was a hole and the maximum sheet carrier densities as high as 4?×?10¹³ cm^?2 and 2?×?10¹³ cm^?2 (electrical activity ratio of about 7% and 3.5%) were measured respectively for the unstrained and 0.8%-tensile-strained Si with Hall mobility around 10–13 cm² V^?1 s^?1. Moreover, mobility degradation was not observed even when sheet carrier density was increased by heat treatment at 500–700 °C. There is a possibility that the local carrier (ionized B atom) concentration around the B AL in Si reaches around 10²¹ cm^?3 and 2-D impurity-band formation with strong Coulomb interaction is expected. The behavior of carrier properties for heat treatment at 500–700 °C implies that thermal diffusion causes broadening of the B AL in Si and decrease of local B concentration.     

Effect of sulfur and copper amounts in sol–gel precursor solution on the growth, crystal properties, and optical properties of Cu2ZnSnS4 films

Cu₂ZnSnS₄ (CZTS) thin films were deposited by sol–gel spin coating using precursor solutions prepared with copper acetate, zinc acetate, tin chloride, and thiourea in methanol and ethylenediamine followed by sulfurization. Sol–gel precursor solutions were prepared with different amounts of sulfur and copper, and their effects on film growth, crystal properties, and optical properties of CZTS films were investigated. CZTS film thickness increased with the amount of metal salt in the precursor solution. This is attributed to an increase in solution viscosity and a decrease in the solution density/viscosity ratio. All CZTS thin films exhibited kesterite structures with absorption coefficients larger than 10⁴ cm^?1 in the visible region. Band gap energy increased with increasing amounts of sulfur and decreasing amounts of copper. The blue shift of the band gap is attributed to changes in the degree of p–d hybridization related to Cu d- and S p-levels. The role of sulfur and copper on Hall mobility and carrier concentration was investigated. By optimizing the metal salt ratio in the precursor, CZTS film with a resistivity of 5.3 × 10^?2 Ωcm were prepared.     

Growth of CZTS thin films by sulfurization of sputtered single-layered Cu–Zn–Sn metallic precursors from an alloy target

Cu₂ZnSnS₄ (CZTS) thin films were prepared by sulfurizing single-layered metallic Cu–Zn–Sn precursors which were deposited by DC magnetron sputtering using a Cu–Zn–Sn ternary alloy target. The composition, microstructure and properties of the CZTS thin films prepared under different sputtering pressure and DC power were investigated. The results showed that the sputtering rate of Cu atom increases as the sputtering pressure and DC power increased. The microstructure of CZTS thin films can be optimized by sputtering pressure and DC power. The CZTS thin film prepared under 1 Pa and 30 W showed a pure Kesterite phase and a dense micro-structure. The direct optical band gap of this CZTS thin film was calculated as 1.49 eV with a high optical absorption coefficient over 10⁴ cm^?1. The Hall measurement showed the film is a p-type semiconductor with a resistivity of 1.06 Ω cm, a carrier concentration of 7.904 × 10¹⁷ cm^?3 and a mobility of 7.47 cm² Vs^?1.     

Structural,optical and electrical properties of SnO<Subscript>2</Subscript>:F thin films deposited by spray pyrolysis for application in thin film solar cells

Fluorine doped tin oxide (FTO) thin films with adequate properties to be used as transparent electrical contact for PV solar cells were synthesised using the spray pyrolysis technique, which provides a low cost operation. The deposition temperature and the fluorine doping have been optimized for achieving a minimum resistivity and maximum optical transmittance. No post-deposition annealing treatments were carried out. The X-ray diffraction study showed that all the FTO films were polycrystalline with a tetragonal crystal structure and preferentially oriented along the (200) direction. The grain size ameliorates with the increase in substrate temperature. The samples deposited with the substrate temperature at 440 °C and fluorine content of 20 wt % exhibited the lowest electrical resistivity (1.8 × 10^?4 Ω cm), as measured by four-point probe. Room-temperature Hall measurements revealed that the 20 wt% films are degenerate and exhibit n-type electrical conductivity with carrier concentration of ~4.6 × 10²⁰ cm^?3, sheet resistance of 6.6 Ω/□ and a mobility of ~25 cm² V^?1 s^?1. In addition, the optimized growth conditions resulted in thin films (~500 nm thickness) with average visible transmittance of 89 % and optical band-gap of 3.90 eV. The electrical and optical characteristics of the deposited films revealed their excellent quality as a TCO material.     

Electrical,optical and magnetoresistive behavior of nanostructured ZnO:Cu thin films deposited by sputtering

Copper doped ZnO (ZnO:Cu) nanostructured films with magnetoresistive behavior were produced by growing ZnO/Cu/ZnO arrays at room temperature (RT) by the sputtering technique on corning glass substrates. The arrays were made with two electrical insulating ZnO films of 50 and 105 nm, and a Cu film of 5 nm, both materials were deposited at RT by the RF- and DC-sputtering technique, respectively. The processing method involves two stages that proceed in the course of the growth process, the main one is originated by the non-equilibrium regime of the sputtering technique, and the second is the diffusion-redistribution of the intermediate Cu film towards the neighborhood ZnO layers aided by the nanocrystalline films character. The influence of applying an additional annealing stage to the arrays in N₂ atmosphere at 250 and 350 °C by periods of 30 min were studied. The resistivity of the ZnO:Cu films can be varied from 0.0034 to 2.83 Ω-cm, corresponding to electron concentrations of 1.12?×?10²¹ and 7.85?×?10¹⁷ cm^?3 with carrier mobility of 1.6 and 2.8 cm²/V s. Measured changes on the magnetoresistance behavior of the films at RT were of ?R?~?3% for annealed samples with electron concentration of 1.12?×?10²¹ cm^?3. The X-ray diffraction measurements show that the films are comprised of nanocrystallites with dimensions between 13 and 20 nm in size with preferred (002) orientation. The transmittance of the films in the visible region was of 83% with an optical band gap of ~?3.3 eV for the low-resistivity samples.     

Preparation of ZnO:Al thin film on transparent TPT substrate at room temperature by RF magnetron sputtering technique

Aluminum doped ZnO thin films (ZnO:Al) deposited on flexible substrates are suitable to be used as transparent conductive oxide (TCO) thin films in solar cells because of the excellent optical and electrical properties. TPT films are a kind of composite materials and are usually used as encapsulation material of solar panels. In this paper, ZnO:Al film was firstly deposited on transparent TPT substrate by RF magnetron sputtering. The structural, optical, and electrical properties of the film were investigated by X-ray diffractometry (XRD), scanning electron microscope (SEM), UV–visible spectrophotometer, as well as Hall Effect Measurement System. Results revealed that the obtained film had a hexagonal structure and a highly preferred orientation with the c-axis perpendicular to the substrate. Also, the film showed a high optical transmittance over 80% in the visible region and a resistivity of about 3.03 × 10^? 1 Ω·cm.     

P-type conductivity in doped and codoped ZnO thin films synthesized by RF magnetron sputtering

N-doped and Al–N codoped ZnO thin films with different volume ratios of N₂ reactive gas were deposited on plane glass substrates using the radio frequency magnetron sputtering method. The phase transition temperature and absorption edge of the ZnO powder were studied by differential scanning calorimetry at different heating rates and with Fourier transform infrared spectroscopy, respectively. The target used for the sputtering was synthesized using a palletize machine. It was sintered at 450 °C for 5 h. The X-ray diffraction results confirm that the thin films have wurtzite hexagonal structures with a very small distortion. The results indicate that the ZnO thin films have obviously enhanced transmittance of up to 80% on an average in the visible region. The Al–N codoped ZnO thin films exhibited the best p-type conductivity with a resistivity of 0.825 Ω-cm, a hole concentration of 6.55 × 10¹⁹ cm^?3, and a Hall mobility of 1.25 cm²/Vs. The p-type conductivity was observed after doping and codoping of the ZnO thin film.     

Quality enhancement of AZO thin films at various thicknesses by introducing ITO buffer layer

Due to the simultaneously superior optical transmittance and low electrical resistivity, transparent conductive electrodes play a significant role in semiconductor electronics. To enhance the electrical properties of these films, one approach is thickness increment which degrades the optical properties. However, a preferred way to optimize both electrical and optical properties of these layers is to introduce a buffer layer. In this work, the effects of buffer layer and film thickness on the structural, electrical, optical and morphological properties of AZO thin films are investigated. Al-doped zinc oxide (AZO) is prepared at various thicknesses of 100 to 300 nm on the bare and 100 nm-thick indium tin oxide (ITO) coated glass substrates by radio frequency sputtering. Results demonstrate that by introducing ITO as a buffer layer, the average values of sheet resistance and strain within the film are decreased (about 76 and 3.3 times lower than films deposited on bare glasses), respectively. Furthermore, the average transmittance of ITO/AZO bilayer is improved nearly 10% regarding single AZO thin film. This indicates that bilayer thin films show better physical properties rather than conventional monolayer thin films. As the AZO film thickness increases, the interplanar spacing, d₍₀₀₂₎, strain within the film and compressive stress of the film in the hexagonal lattice, decreases indicating the higher yield of AZO crystal. Moreover, with the growth in film thickness, carrier concentration and optical band gap (E_g) of AZO film are increased from 4.62?×?10¹⁹ to 8.21?×?10¹⁹ cm^?3 and from 3.55 to 3.62 eV, respectively due to the Burstein-Moss (BM) effect. The refractive index of AZO thin film is obtained in the range of 2.24–2.26. With the presence of ITO buffer layer, the AZO thin film exhibits a resistivity as low as 6?×?10^?4 Ω cm, a sheet resistance of 15 Ω/sq and a high figure of merit (FOM) of 1.19?×?10⁴ (Ω cm)^?1 at a film thickness of 300 nm. As a result, the quality of AZO thin films deposited on ITO buffer layer is found to be superior regarding those grown on a bare glass substrate. This study has been performed over these two substrates because of their significant usage in the organic light emitting diodes and photovoltaic applications as an enhanced carrier injecting electrodes.     

Structural,electrical, optical properties and reliability of ultra-thin tin doped indium oxide films for touch panels

Ultra-thin ITO films with thickness of 4–56 nm were deposited on glass by dc magnetron sputtering using 5 wt% SnO₂ doped ITO target. The effect of film thickness on the structural, electrical, optical properties and reliability was investigated for its application to touch panels. The 4 nm thick ITO film shows amorphous structure and other films present polycrystalline structure and the (222) preferred orientation. The ultra-thin ITO films show smooth surface with low Ra surface roughness smaller than 1 nm. The sheet resistance and visible transmittance of the ITO films decrease with the increase in film thickness. The 4 nm thick ITO film shows the highest resistivity (3.08 × 10^?3 Ω cm) with low carrier density and Hall mobility, and other films have excellent conductivity (<4.0 × 10^?4 Ω cm). The ITO films show high transmittance (>85 %) in visible light range and do not generate interference ripples between film and substrate interface. The ITO films with thickness of 18–56 nm show stable reliability under high temperature, high temperature & high humidity and alkaline environmental conditions. The only electrical degradation corresponds to the increase of sheet resistance in the ITO films with thickness of 4–12 nm.