Optoelectronic Properties of Fluorine and Cobalt Co-Doped Tin Oxide Thin Films Deposited by Chemical Spray Pyrolysis

Abstract

Transparent conducting Cobalt-fluorine co-doped tin oxide (SnO2: (Co, F)) thin filmswere deposited onto preheated glass substrates using the chemical spray pyrolysis method. The ([Co2+]/[Sn4+]) atomic concentration ratio (y)in the spray solution was varied between 0 and 5 at. %. The structural, electrical, optical and photoluminescence properties of these films were studied. It is found that the thin films are polycrystalline with a tetragonal crystal structure corresponding to SnO2 phase having a preferred orientation along the (200) plane. Transmission and reflection spectra reveal the presence of interference fringes indicating thickness uniformity and surface homogeneity of the deposited thin films. The electrical resistivity (ρ), volume carrier concentration density (Nv), surface carrier concentration density (Ns) and Hall mobility (μ) of the synthesized thin films were determined from the Hall Effect measurements in the Van der Paw-configuration and the following results were obtained: n-type conductivity in all deposited films, a low resistivity of 1.16×10-2 Ω.cm, and a high Hall mobility of 15.13×102 cm2.V-1.s-1with Co concentration equals to 3 at. %. These results show that the electrical properties of these thin films where greatly improved making them suitable as ohmic contact in photovoltaic application devices.

Effect of substrate temperature on physical properties of Co doped SnS2 thin films deposited by ultrasonic spray pyrolysis

“…where k = 0.94 is the shape factor, λ is the wavelength of CuKα radiation source (λ = 1.5406 Ǻ), β is the (full width half maxi-mum) FWHM value of the respective diffraction peak, and θ is the Bragg angle. The crystallite size values of Co doped SnS 2 thin films are lower than that of pure SnS 2 even with the change of substrate temperature [32]. Because Sn 2+ has a bigger ionic radius then Co 2+ .…”

“…Hexagonal structure remains stable for SnS 2 whatever the temperature change, it is a layered material with a cadmium iodide (CdI2) type structure [2]. Thereafter, tin sulfide exists in several phases such as SnS, SnS 2 Sn 2 S 3 and Sn 3 S 4 lead to bonding characteristics of tin and sulfur, only at higher temperatures (upper to 350° C) the SnS 2 phase appear [32]. It has an n-type conductivity with a wide optical band gap varying between 2.40 and 2.88 eV [3,4], a light absorber (absorption coefficient up to 10 4 cm -1 ) and relatively high charge carrier mobility in the range of 18.3 to 230 cm 2 /V.…”

“…SnS 2 can be explored as a window layer [8] as well as an alternate buffer layer in thin film heterojunction solar cells applications [9]. Several methods are used for the deposition of SnS 2 thin films such as; chemical vapor deposition [10], vacuum evaporation [11], molecular beam epitaxy [12], dip coating technique [13], SILAR [14], and ultrasonic spray pyrolysis [15][16][17][18][19].…”

A review of novel methods to improve the optical and electrical properties of n-type and p-type sulphides and oxides: leading the frontiers of semiconductor technology

“…It was reported that SnO 2 : Co films prepared by sol-gel method had a higher carrier concentration and mobility than undoped SnO 2 films, resulting in improved electrical conductivity. The films also showed enhanced visible light absorption and photocatalytic activity [111]. Alloying zinc oxide (ZnO) with copper (Cu) has been shown to improve its electrical and optical properties.…”

First principles study of the electronic structure of antimony (Sb) and samarium (Sm) doped tin dioxide (SnO2) based on big data analysis

“…Each SnO2 cell contains two Sn atoms and four O atoms with a space group of p42/mnm (No. 134), lattice constants a=b=0.4737 nm, c=0.3186 nm, and α=β=γ=90° [22][23]. The SnO2 crystal anion coordination number is 6:3, and each Sn ion is adjacent to six oxygen ions, and each oxygen ion is adjacent to 3 tin ions adjacent.…”