Properties of CdS films doped with magnesium and fluorine

Abstract

Nanostructured CdS thin films co-doped with Mg and F were prepared on glass substrates maintained at 400°C by spray technique using perfume atomiser. Structural, morphological, optical and electrical properties of the films were investigated in order to study the effect of Mg, F doping concentration. XRD patterns confirm that both undoped and co-doped CdS films exhibit hexagonal crystal structure with preferential orientation along the (0 0 2) plane. Crystallite size decreased from 33.19 to 24.51 nm with increase in Mg, F concentration. Increased transparency and blue shift in optical band gap from 2.48 to 2.75 eV is observed with increase in Mg, F concentration. All the films have resistivity in the order of 10 −2 Ω cm which decreased with co-doping. Improved optical transparency, widened band gap and decreased resistivity were observed for the CdS films simultaneously doped with Mg and F.

Structural, electrical and optical properties of CdS thin films and the effect of annealing on photoconductivity

“…Table 2 illustrates the values of direct optical energy gap and the optical constants [refractive index (n), extinction coefficient (k), the real part ( r) and the imaginary part ( i) of dielectric constant ]. Our results are similar to that obtained by Ashour [13] , Moss [15] and Sivaraman [16]. The photoconductivity of the as deposited and annealed films has been determined.…”

Role of Cu/S ratio and Mg doping on modification of structural and optical characteristics of nano CuS

“…It is noticed that the number of bands increased with the increased Cu:S ratio. 38 In case of samples with different Cu:S amount ratio, the band-toband transitions are blue shifted similar to the energy gap behavior obtained from UV-analysis, and this shift is due to the crystallite size effect as discussed in XRD part, In our case as Cu:S ratio increased, the crystallite size decreased, thus the defects increased and number of bands increased (see XRD part).…”

“…36 The violet peak can be attributed to near band edge electronic transition (band-to-band transition). 38 In case of samples with different Cu:S amount ratio, the band-toband transitions are blue shifted similar to the energy gap behavior obtained from UV-analysis, and this shift is due to the crystallite size effect as discussed in XRD part, amount of defects created inside the band gap. The blue color peak belongs to transitions of trapped electrons from defects levels (probably S-vacancy states) to the valence band.…”

Investigations on the Properties of Nanostructured Mg-Doped Sn2S3 Thin Films towards Photovoltaic Applications

“…It is observed that all the films exhibit emission peaks at 485 nm (2.56 eV), 544 nm (2.28 eV) and 608 nm (2.04 eV). The peak at 485 nm can be attributed to the transitions of trapped electrons from donor levels to the valence band which can be assigned to defect states, probably S vacancy states [24]. The green band emission observed at 2.28 eV has been originated from the transition of the increased V s donors to recombine with S interstitials (I s ) acceptors in the valence band [25].…”