Optical Properties of Synthesized Hexagonal CdTe Nanoparticles Having Hexagonal Phase: Density Functional Theory‐Supported Calculation of Bandgap and Density of States. Issue 1 (20th September 2022)

• Record Type: Journal Article
• Authors: Basak, Sanghita; Das, Ratan
• Is Part Of: Physica status solidi. Volume 260:Issue 1(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-09-20
• Subjects: CdTe nanoparticles -- density functional theory calculations -- density of states -- hexagonal shape -- optical bandgap; Solid state physics -- Periodicals; Solids -- Periodicals; Atomic structure -- Periodicals; 530.41
• DOI: 10.1002/pssb.202200157
• Languages: English
• ISSNs: 0370-1972

Abstract

Abstract : Hexagonal CdTe nanoparticles with hexagonal phase are chemically prepared. Transmission electron microscopic analysis shows that the prepared nanoparticles are hexagonal in shape. Again, in the selected‐area electron diffraction pattern, ring‐shaped identical patterns containing sharp bright spots are observed, which confirm that nanoparticles are polycrystalline in nature. The observed X‐ray diffraction (XRD) peaks on matching with the standard data confirm the formation of hexagonal phase. Again, from the observed absorption peak at 449 nm, the bandgap is calculated as 2.4 eV using Tauc's equation, which is found to be slightly higher compared with the reported bandgap of cubic CdTe nanoparticles. Further, Urbach energy is found as 534 meV, which indicates the presence of defect states in the nanoparticles, and the refractive index of synthesized nanoparticles is calculated as 2.6. Rietveld refinement of X‐ray data is performed for the determination of lattice structural parameters, which is then used for the computation of density functional theory (DFT)‐based bandgap using Quantum ESPRESSO code. Finally, the bandgap obtained from the theoretical study and experimental study is compared. The innovation herein lies in the use of experimental XRD data for bandgap calculation using DFT. Abstract : Transmission electron microscopic and X‐ray diffraction (XRD) analysis shows that the prepared CdTe nanoparticles are hexagonal in shape with hexagonal phase. The bandgap is calculated as 2.4 eV. Rietveld refinement data are used for bandgap calculation using Quantum ESPRESSO code. The innovation herein lies in the use of XRD data for bandgap calculation using density functional theory.