Influence of Oxygen Flow Ratio on Properties of Zn₂SnO₄ Thin Films Deposited by RF Magnetron Sputtering

Abstract

Zinc stannate (Zn2SnO4) thin films were deposited by RF magnetron sputtering on silica substrates at various [O2/(Ar+O2)] flow ratios. The influences of the [O2/(Ar+O2)] flow ratio on the crystalline structure, and the optical and electrical properties have been investigated. No sharp X-ray diffraction (XRD) peaks were observed in as-deposited thin films. After postdeposition annealing in air at 750°C, the thin films showed a preferred orientation of (111). The thin films exhibited a high transmittance in the visible spectrum irrespective of the [O2/(Ar+O2)] flow ratio or postdeposition annealing. The optical band gap was estimated to be 4.1 eV by analyzing the optical spectra of thin films annealed at 750°C. The composition ratio of Zn/Sn for thin films deposited in an Ar/O2 mixture was 2.0 and their electrical resistivity was on the order of 105 Ω·cm. In contrast, the composition ratio of Zn/Sn for a thin film deposited in pure Ar was 1.5 and an electrical resistivity of 4.1 ×10-2 Ω·cm was observed.

Synthesis and photoluminescence of Zn2SnO4 nanowires

“…Zn 2 SnO 4 has been considered as a promising candidate for chemical sensors, photoelectrical devices, transparent conducting electrodes, functional coatings and photocatalysts [2][3][4][5][6][7][8][9][10][11][12]. Up to now, most researches have focused on the synthesis and application of Zn 2 SnO 4 films and nanoparticles.…”

Optimisation of amorphous zinc tin oxide thin film transistors by remote-plasma reactive sputtering

“…An a-ZTO film prepared by rf magnetron sputtering at 500 C also shows a small shift of transmittance towards lower wavelength (blue shift) upon annealing at 600 C, but a large blue shift upon annealing at 750 C, which coincides with the appearance of crystalline peaks. 7 On the contrary, a red shift in the optical band gap ($0.5 eV) in MOCVD ZnO is reported upon annealing at 500 C, which also coincides with an increase in the crystalline phase. 47 Since our films still remain amorphous after annealing, the small change of the optical band gap in our work is reasonable.…”

“…2016) deposited by rf magnetron sputtering from ceramic targets but is less pronounced (up to a factor of 1.3). 6,7,11,54 Preferential sputtering is a common phenomenon whenever a target containing two or more elements is subjected to a particle impact, and it arises from the differences in mass, chemical binding and bombardment-induced Gibbsian segregation which are in turn related to the sputtering yield. 55 Using 500 eV Ar þ ion as the sputtering gas, the sputtering yield of elemental tin and zinc are estimated to be 1.56 and 4.6, respectively.…”

“…22 Various deposition techniques, such as sol-gel, 23,24 atomic layer deposition (ALD), 25,26 metal organic chemical vapour deposition (MOCVD), 27 and pulsed laser deposition (PLD), 21,28 have been reported for ZTO, however, rf or dc magnetron sputtering is most commonly used. [6][7][8][9][10]20,[29][30][31][32] Ceramic ZTO targets with at. % of Zn: Sn of either 1:1 or ).…”

Thermal evaporation route to zinc stannate nanowires and the cathodoluminescence of the individual nanowires

“…As one of the most important TCO semiconductors with wide band gap of 3.6 eV, zinc stannate (Zn 2 SnO 4 ) has been considered as promising materials as chemical sensors, TC electrodes and photocatalysts due to its high chemical sensitivity, low visible absorption and low electrical conductivity [6][7][8][9][10][11]. Recently, Zn 2 SnO 4 nanowires have attracted considerable attentions due to their potential scientific studies and applications in optoelectronics and photocatalysis [12,13].…”