Photoluminescence of Nanocrystalline CdS Thin Films Prepared by Chemical Bath Deposition

Abstract

Nanocrystalline cadmium sulfide (CdS) thin films were prepared using chemical bath deposition in a solution bath containing CdSO 4 , SC(NH 2 ) 2 , and NH 4 OH. The CdS thin films were investigated using X-ray diffraction (XRD), photoluminescence (PL), and Fourier transform infrared spectroscopy (FTIR). The as-deposited CdS thin film prepared at 80°C for 60 min had a cubic phase with homogeneous and small grains. In the PL spectrum of the 2,900 Å-thick CdS thin film, the broad red band around 1.7 eV and the broad high-energy band around 2.7 eV are attributed to the S vacancy and the band-to-band transition, respectively. As the deposition time increases to over 90 min, the PL intensity from the band-to-band transition significantly increases. The temperature dependence of the PL intensity for the CdS thin films was studied from 16 to 300 K. The E A and E B activation energies are obtained by fitting the temperature dependence of the PL intensity. The E A and E B are caused by the deep trap and shallow surface traps, respectively. From the FTIR analysis of the CdS thin films, a broad absorption band of the OH stretching vibration in the range 3,000-3,600 cm -1 and the peak of the CN stretching vibration at 2,000 cm -1 were found.

Synthesis of Water-Soluble Antimony Sulfide Quantum Dots and Their Photoelectric Properties

“…According to the previous report, CBD-synthesized Sb 2 S 3 nanocrystals show a weak band edge emission peaked at around 610 nm (2.03 eV) presumably resulting from excitons and a sulfur vacancy-related strong emission peaked at 717 nm (1.72 eV). For water-soluble Sb 2 S 3 QDs here, the green emission around 510 nm presumably results from excitons [21, 22], which is well known and widely reported for semiconductor nanocrystals [23], suggesting the quantum size effect (QSE) brings a broader band gap for Sb 2 S 3 QDs. The near-infrared emission around 880 nm may be attributed to the presence of stoichiometry-related point defects.…”

Investigation of Boron-Doped CdS Films Deposited by Ultrasonic Spray Pyrolysis Technique

“…where β is the half peak width as radian of the maximum intensity peak, D is the particle size, θ is the Bragg angle and λ is the X-ray wavelength. Also, δ is the dislocation density of the samples which is given by Williamson and Smallman's relation (Park, 2010). These values are given in Table 2. = 1 2 ⁄ (2)…”

Optical Constants and Dispersion Parameters of CdS Thin Film Prepared by Chemical Bath Deposition

“…The alkaline solution bath, containing cadmium sulphate, thiourea, and ammonium hydroxide, was maintained at 80℃, and the pH value of the aqueous solution was 10 [24]. The deposited CdS thin film was rinsed in deionized water, and cleaned ultrasonically.…”