Understanding the shrinkage of optical absorption edges of nanostructured Cd-Zn sulphide films for photothermal applications

Md Sohrab Hossain, Humayun Kabir, M. Mahbubur Rahman, Kamrul Hasan, Muhammad Shahriar Bashar, Mashudur Rahman, Md Abdul Gafur, Shariful Islam, Amun Amri, Zhong Tao Jiang, Mohammednoor Altarawneh, Bogdan Z. Dlugogorski

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)


In this article Cd-Zn sulphide thin films deposited onto soda lime glass substrates via chemical bath deposition (CBD) technique were investigated for photovoltaic applications. The synthesized films were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet visible (UV–vis) spectroscopic methodologies. A higher degree of crystallinity of the films was attained with the increase of film thicknesses. SEM micrographs exhibited a partial crystalline structure with a particulate appearance surrounded by the amorphous grain boundaries. The optical absorbance and absorption coefficient of the films were also enhanced significantly with the increase in film thicknesses. Optical band-gap analysis indicated a monotonic decrease in direct and indirect band-gaps with the increase of thicknesses of the films. The presence of direct and indirect transitional energies due to the exponential falling edges of the absorption curves may either be due to the lack of long-range order or to the existence of defects in the films. The declination of the optical absorption edges was also confirmed via Urbach energy and steepness parameters studies.

Original languageEnglish
Pages (from-to)854-862
Number of pages9
JournalApplied Surface Science
Publication statusPublished - Jan 15 2017
Externally publishedYes


  • Absorption edges
  • Band gap
  • Crystallinity
  • SEM
  • UV–vis
  • XRD

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Surfaces and Interfaces


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