Physical properties of Dy and La doped SnO₂ thin films prepared by a cost effective vapour deposition technique

Abstract

Stannous oxide (SnO 2 ) thin film is one of the most widely used n-type transparent semi-conductor films in electronics, electro-optics and solar energy conversion. By achieving controlled non-stoichiometry, we can get good transparency and high electrical conductivity simultaneously in SnO 2 thin films. Dy and La doped SnO 2 thin films have been prepared by a cost effective vapour deposition technique. The structural, photoelectronic, optical and electrical properties of the doped and undoped films were studied. The results of X-ray Diffraction studies reveals the polycrystalline nature of the films with preferential orientation along the (101), (211) and (301) planes and their average grain size variation for different deposition temperature. Photoconductivity and Photovoltaic studies of the films were also performed. The optical properties of these films were studied by measuring their optical transmission as a function of wavelength. The optical transmission is found to be increased on Dy doping and decreased on La doping. The band gap, refractive index and thickness of the films were calculated from U-V transmittance and Absorption graphs. The optical band gap of undoped film is found to be 4.08 eV, but on doping it shifts to lower energies and then increases on increasing the concentration of both dopants. Its electrical parameters such as sheet resistance, resistivity, mobility, Hall coefficient, and carrier concentration were determined by Four Probe, Van der Pauw and Hall Probe method. On doping with Dy, carrier conversion takes place from n-type to p-type and p-conductivity dominates. On La doping no carrier conversion takes place but resistivity decreases.

Photoluminescence Studies on Nanocrystalline Tin Oxide Powder for Optoelectronic Devices

“…The changing of the annealing temperatures from 200 to 800℃ which decreased the density of nucleation centers as shown in Fig. 3 As the temperature increases, a smaller number of unit cells start to grow, which results in large grain size [16]. A smaller crystallite size exhibits larger cell volume and minimum number of unit cells was present.…”

Band Gap Tuning in Transition Metal and Rare-Earth-Ion-Doped TiO2, CeO2, and SnO2 Nanoparticles

“…Let us emphasize that there are some discrepancies by the RE ion doping. A decrease in for small doping concentrations of different RE ions (for example, Sm, La, Dy, Nd, Eu, Er, and Tb) is also reported in TiO , CeO , or SnO NPs [ 70 , 85 , 90 , 91 , 92 , 93 , 94 ]. However, some authors have observed an increase in the band-gap energy in Sm [ 95 ] and Yb, Sc [ 45 ]-doped TiO NPs, and Pr-doped CeO NPs [ 96 ].…”

“…Let us emphasize that there are some discrepancies by the RE ion doping. A decrease in E g for small doping concentrations of different RE ions (for example, Sm, La, Dy, Nd, Eu, Er, and Tb) is also reported in TiO 2 , CeO 2 , or SnO 2 NPs [70,85,[90][91][92][93][94]. However, some authors have observed an increase in the band-gap energy E g in Sm [95] and Yb, Sc [45] It must be mentioned that pure bulk TiO 2 without defects and impurities is diamagnetic due to the presence of Ti 4+ , which has no unpaired electrons, making it diamagnetic.…”

Sol-Gel Processed Yttrium-Doped SnO2 Thin Film Transistors

“…The degraded field-effect mobility and on-current originated from a significant decrease in the free carrier concentration, originating from the oxygen vacancy in metal oxide semiconductors. In addition, the Y 3+ -Sn 4+ substitution reaction might generate an extra hole carrier, leading to a decrease in free carrier concentration by compensating for electron carrier concentration [26]. In addition, the threshold voltage exhibited a positive shift, in particular, from 0.5 wt% Y.…”