Optical Parameters of Nanocrystalline SnO2:F Thin Films Prepared by the Spray Pyrolysis Method

Abstract

SnO 2 thin films are usually used as fore contacts in superstrate thin film solar cells such as thin film CdS/CdTe solar cells. Doping SnO 2 with fluorine improves its electrical properties and increases its optical bandgap energy besides improving other optical parameters. SnO 2 :F thin films of thickness around 200 nm were deposited on glass substrates by the spray pyrolysis method at a substrate temperature T s = 480°C. X-ray diffraction and scanning electron microscopy showed that the films are nanocrystalline. The transmittance of the films was measured at room temperature in the wavelength range 290-1100 nm, and used to calculate the reflectance, which was in turn used to deduce the optical parameters, such as the extinction coefficient, refractive index, real and imaginary parts of the dielectric constant, and energy loss. The relationships between these parameters and photon energy were investigated and compared with the results obtained by other authors.

Controlled optoelectronic properties and abrupt change in photosensitivity by suppressing density of oxygen vacancies in SnO2 nanocrystalline thin films prepared at various spray-deposition temperatures

“…Comparable values of optical transparency have been previously reported in several works (e.g. [5,46,47]). Based on the above-mentioned observations, all the TDO thin films investigated here exhibit excellent optical transparency in the visible region, whereas the TCO applications such as optoelectronic devices require at least 80% optical transparency [48,49].…”

“…In the current work, the relatively high optical transmission in the visible region and near-infrared region allows the prepared TDO thin films to be with great potentials for practical uses in optoelectronic devices (e.g. such as solar cells [5] and energy efficient windows [6]). As it is observed from the XRD results, increasing the substrate temperature reduces the density of the grain boundaries within the TDO thin films resulting in larger grain size.…”

“…As a transparent conducting oxide (TCO) material, tin dioxide is one of the most significant metal oxides usually found in a rutile structure [1]. The oxide SnO 2 have received extensive interest due to its wide optical band gap (∼3.6 eV), high exciton binding energy (130 meV) [2][3][4], high optical transparency in the visible region of the electromagnetic spectrum as well as high reflectivity in infra-red region [5,6] and high n-type conductivity at room temperature [7][8][9][10]. These properties of tin dioxide make it an excellent material for use in photo catalysis [11], solid state gas sensors [12], photothermal converser of solar energy [13], optoelectronic devices [14], memories, transparent and flexible electronics and integrated logic circuits [15][16][17].…”

Major role of intrinsic defects in optical and electrical properties adopting a highly defect-controlled photoconductivity in spin-coated α-MoO3 thin films gained after UV illumination

“…Obtained Standard (JCPDS) gained by the later heat treatment that results in an atomic rearrangement and a consequent increase in the crystallite size by assembling smaller crystallites to form larger grains [24,25]. This implies reduction in the intrinsic defect density by suppressing the number of these defects that may act as trapping centers.…”

Spray deposited thin films of SnO2: F/CdS: In bilayers produced using different fluorine sources: NH4F and HF

“…There are different experimental routs to prepare SnO2 thin films, such as reactive sputtering [7], thermal evaporation [8][9][10], chemical vapor deposition [8,11], dip coating [12] and spray pyrolysis [13][14][15][16][17][18][19][20][21][22][23][24][25]. At the same time CdS thin films can be prepared by different methods such as chemical bath deposition [26], thermal evaporation [27][28][29], screen printing [30] and spray pyrolysis [14,28,[31][32][33][34][35][36][37][38][39][40][41][42][43][44][45].…”