Bismuth-content dependent of the polarized Raman spectra of the InPBi alloys

TL;DR

This study systematically explores how varying bismuth content affects the polarized Raman spectra of InPBi alloys, revealing insights into lattice substitution, vibrational mode shifts, and electron concentration effects.

Contribution

It provides the first detailed analysis of bismuth-dependent polarized Raman spectra in InPBi alloys, linking Bi content to vibrational and electronic properties.

Findings

Bi content causes exponential increase in InBi-like Raman mode intensity.

InP-like LO modes exhibit a linear red-shift with Bi incorporation.

LOPC mode intensities correlate with electron concentrations.

Abstract

We have systematically investigated the optical properties of the InP1-xBix ternary alloys with 0<x<2.46%, using high resolution polarized Raman scattering measurement. Both InP-like and InBi-like optical vibration modes (LO) were identified in all the samples, suggesting most of the Bi-atoms are incorporated into the lattice sites to substitute P-atoms. And the intensity of the InBi-like Raman modes increase exponentially as Bi-content increasing. Linearly red-shift of the InP-like longitudinal optical vibration modes was observed to be 1.1 cm-1 of percent Bi, while that of the InP-like optical vibration overtones (2LO) were nearly doubled. In addition, through comparing the difference between the Z(X,X)Z and Z(X,Y)Z Raman spectra, Longitudinal Optical Plasmon Coupled (LOPC) modes are identified in all the samples, and their intensities are found to be proportional to the electron concentrations.