Study of CuInTe₂ Quantum Dots under Extreme Conditions

Authors

Howard Yanxon, University of Nevada, Las VegasFollow
Ravhi Kumar, University of Nevada, Las VegasFollow

Funder

Ronald E. McNair Scholars Summer Research Institute; Center for Academic Enrichment and Outreach

Document Type

Poster

Publication Date

2015

Publisher

University of Nevada, Las Vegas; Center for Academic Enrichment and Outreach

Publisher Location

Las Vegas (Nev.)

Abstract

In recent years, Quantum Dot (QD) materials have attracted considerable interest due to their versatile properties and potential applications in electronics, biology, and optoelectronics, i.e. photovoltaic solar cell materials [1-2].

In 2000, RincÓn et al. reported an extensive study of the bulk material of CuInTe₂ along with its comparison to its ordered defect compounds [3]. The chalcopyrite structure consists of eight atoms per unit cell. This means there are 24 vibrational modes expected for the tetragonal structure. Out of the 24 modes, 21 vibrational modes belong to optical modes, and the other 3 modes are acoustical modes. The irreducible representation of the optical modes at Γ point is given as,

Γ = 1A₁ + 2A₂ + 3B₁ + 3B₂ + 6E,

where E modes are twofold degenerate vibrations. Theoretically, other than A2 modes, the optical modes at Γ point should be Raman-active [3].

At ambient conditions, both bulk and nanoparticle of CuInTe₂ exhibit chalcopyrite structure [3-5]. In bulk, the CuInTe₂ chalcopyrite structure is reported to undergo a pressure-induced phase transition to an orthorhombic (d-Cmcm) structure around 3.6 GPa (see Fig. 1) [5]. In QDs, Kosuga et al reported I-42d as the space group of CuInTe₂ [6]. The I-42d space group is translated to D2d or Vd point group. At ambient conditions, the Raman peaks of CuInTe₂ nanocubes were observed at 121 cm-1 and 174 cm-1. The 121 cm-1 and 174 cm-1 have been assigned as A1 and E or B2 (LO) modes, respectively. The A1 mode of CuInTe₂ is due to of the motion of tellurium atoms with the idle Copper and Indium atoms [7].

This present project aims on investigation the phase transition properties of CuInTe₂ QDs under high pressure. We have used high pressure Raman Spectroscopy to map the variation of vibrational modes up to 7.7 GPa. A pressure-induced phase transition is observed around 2.9 GPa for the QDs in our experiment.

Keywords

Quantum Dots; CuInTe2; Raman Spectroscopy

Disciplines

Physics

File Format

pdf

File Size

818 KB

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

Repository Citation

Yanxon, H., Kumar, R. (2015). Study of CuInTe₂ Quantum Dots under Extreme Conditions.
Available at: https://digitalscholarship.unlv.edu/mcnair_posters/74