Role of polarized tip-enhanced Raman spectroscopy in the enhancement of interface optical phonon modes in AlGaN multi-quantum wells

Authors

  • A.K. Sivadasan Homi Bhabha National Institute
  • Prajit Dhara Birla Institute of Technology and Science Pilani
  • Chirantan Singha University of Calcutta
  • Raktima Basu Homi Bhabha National Institute
  • Santanu Parida Homi Bhabha National Institute
  • A. Bhattacharyya University of Calcutta
  • Kishore K. Madapu Homi Bhabha National Institute
  • Sandip Dhara Indira Gandhi Centre for Atomic Research

Keywords:

multi-quantum well, surface optical phonon mode, tip-enhanced Raman spectroscopy, ters, AlGaN, superlattice

Abstract

Group III nitride based two-dimensional multi-quantum well (MQW) nanostructures find remarkable applications in the visible to ultraviolet light sources. The interface optical (IFO) phonon modes in a c-axis oriented superlattice of [Al0.35Ga0.65N (~1.75 nm)/Al0.55Ga0.45N (~2nm)]20 MQWs are observed using tip-enhanced Raman spectroscopic (TERS) studies. The near-field studies using TERS probe with an Au spherical nanoparticle of ~ 200 nm diameter were carried out at ambient conditions showing approximately two to three orders of enhancement in the Raman intensities.  The interface phonon mode belonging to E1 symmetry [IFO(E1)] vibrating normal to the c-axis of MQWs appeared to be more prominent in the case of TERS measurement compared to that for the other interface phonon mode of A1 symmetry. The confined electric field of the polarized electro-magnetic excitation using TERS probe, parallel to the plane of the interface of MQW, is made responsible for the plasmonic enhancement of IFO(E1) phonon mode. The confinement was verified using finite-difference time-domain simulation.

Author Biography

Sandip Dhara, Indira Gandhi Centre for Atomic Research

Surface and Nanoscience Division, Indira Gandhi Centre for Atomic Research, Homi Bhabha National Institute, Kalpakkam-603102, India

TERS with AlGaN

Downloads

Published

2020-01-02

How to Cite

Sivadasan, A., Dhara, P., Singha, C., Basu, R., Parida, S., Bhattacharyya, A., Madapu, K. K., & Dhara, S. (2020). Role of polarized tip-enhanced Raman spectroscopy in the enhancement of interface optical phonon modes in AlGaN multi-quantum wells. Journal of Materials NanoScience, 7(1), 19-23. Retrieved from http://thesciencein.org/journal/index.php/jmns/article/view/97

Issue

Section

Research Articles