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

Abstract

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.

Effects of air annealing on CdS quantum dots thin film grown at room temperature by CBD technique intended for photosensor applications

“…However, it was observed that the air annealing of the samples beyond 350 8C resulted in the formation of CdO on account of its oxidation [29]. The observed improvement in the crystallites of samples can be correlated with the optical study, reflecting red shift in optical band gap of the material which is justified by increased crystallite size and crystalline quality [30].…”

“…The calculated room temperature resistivity of as-deposited, 150, 250 and 350 8C annealed samples were 16, 8.8, 2.6 and 1.6 MV cm, respectively. The increase in annealing temperature is responsible for decrease in band gap, resistivity and activation energy [30]. The activation energy was calculated by the following formula E a ðin eVÞ ¼ 2:303  k  slope where E a , activation energy in electron volt; K, Boltzman's constant (8.6  10 À5 eV/K).…”

Grain growth and crack formation in NiO thin films by swift heavy ion irradiation

“…Interestingly we observe grain growth at some fluences of irradiation. In a few cases, irradiation has been shown to result into growth of nanoparticle grains [4,5,[24][25][26][27]. This is particularly true for thin solid films, which are not in thermodynamic equilibrium.…”

Observation of grain growth in swift heavy ion irradiated NiO thin films

“…On the contrary we observe grain growth and texturing in NiO thin films subjected to 120 MeV Au irradiation. In a few cases irradiation has been shown to result in improvement in crystallization [3,[6][7][8][9][10]. This is particularly true for thin solid films, which are not in thermodynamic equilibrium.…”