Engineering of nanocrystalline cadmium sulfide thin films by using swift heavy ions

Swift heavy ion (SHI) irradiation experiments have been performed on as-deposited nanocrystalline cadmium sulfide (CdS) thin films by using 100 MeV Au8+ ions with 5 × 1012 ions cm-2. In addition, the as-deposited films were annealed at 300 °C in air for 1 h. Structural, optical and electrical properties of pristine (as-deposited), annealed and irradiated thin films were carried out by using x-ray diffraction (XRD), energy dispersive spectra, scanning electron microscopy, atomic force microscopy, UV-VIS spectroscopy and Arrhenius plots for resistivity and thermoemf, respectively. XRD shows the intrinsic peak of (0 0 2) for the hexagonal phase of CdS. After annealing and SHI irradiation this peak was enhanced drastically and dramatically, showing the dominant orientation in this plane. The grain growth observed in these two post-deposition processes was different. This resulted in a decrease in resistivity of the annealed and the irradiated samples by one and two orders from the pristine sample, respectively. © 2007 IOP Publishing Ltd

Growth and characterization of CdZn(S<inf>1-x</inf>Se<inf>x</inf>)<inf>2</inf> alloy film deposited by solution growth technique

The n-CdZn(S1-xSex)2 thin films have been deposited by solution growth technique. The various deposition parameters such as pH of solution (10.5), time, concentration of ions and temperature have been optimized. In order to achieve uniform films, triethanolamine (TEA) has been used. The as deposited films have been annealed in rapid thermal annealing (RTA) system at 250 °C in air for 5 min. The surface morphology, compositional ratio, structural properties have been studied by SEM, EDAX and XRD techniques, respectively. The XRD study shows that all the films are of polycrystalline in nature and exhibits the hexagonal and cubic structure for the composition x = 0.0-0.7 and x > 0.7, respectively. For hexagonal structure, the lattice constants 'a' varies from 4.13 Å to 4.04 Å and 'c' = 6.615 Å to 6.514 Å and for cubic structure 'a' varies from 5.629 Å to 5.598 Å. The absorption coefficient 'α' varies in the range 2 × 104 cm-1 to 17 × 104 cm-1. Band gap values were calculated from the transmittance spectra, which showed a non-linear variation with respect to composition 'x'. © 2006 Elsevier B.V. All rights reserved

A comparative study of the physical properties of CdS, Bi<inf>2</inf>S<inf>3</inf> and composite CdS-Bi<inf>2</inf>S<inf>3</inf> thin films for photosensor application

Thin films of CdS, Bi2S3 and composite CdS-Bi2S3 have been deposited using modified chemical bath deposition (M-CBD) technique. The various preparative parameters were optimized to obtain good quality thin films. The as-deposited films of CdS, Bi2S3 and composite were annealed in Ar gas at 573 K for 1 h. A comparative study was made for as-deposited and annealed CdS, Bi2S3 and composite thin films. Annealing showed no change in crystal structure of these as-deposited films. However, an enhancement in grain size was observed by AFM studies. In addition change in band gap with annealing was seen. A study of spectral response, photosensitivity showed that the films can be used as a photosensor. © 2007 Elsevier B.V. All rights reserved

Gigantic irradiation effect of 100 MeV Au

Gigantic deformations were found for the copper sulfide (Cu1.4S and Cu2S) thin films irradiated with 100 MeV Au8+ swift heavy ions (SHI) for 1011 and 1012 ions cm-2 fluencies. It was observed that the deformation due to SHI is dependent on the chemical composition of the film. The optical band gap (Eg) of the Cu1.4S was blue shifted, whereas that of Cu2S was red shifted. The surface modifications were also different for these two compositions. These effects were studied by using the atomic force microscopy and scanning electron microscopy. The results are explained in the light of thermal spike model

Modifications of structural, optical and electrical properties of nanocrystalline bismuth sulphide by using swift heavy ions

Modified chemical bath deposited (MCBD) bismuth sulphide (Bi2S3) thin films' structural, optical and electrical properties are engineered separately by annealing in air for 1 h at 300 °C and irradiating with 100 MeV Au swift heavy ions (SHI) at 5 × 1012 ions/cm2 fluence. It is observed that the band gap of the films gets red shifted after annealing and irradiation from pristine (as deposited) films. In addition, there is an increase in the grain size of the films due to both annealing and irradiation, leading to the decrease in resistivity and increase in thermoemf of the films. These results were explained in the light of thermal spike model. © 2008 Elsevier B.V. All rights reserved