Analysis of Raman modes in Mn-doped ZnO nanocrystals

TL;DR

This study investigates how manganese doping affects the vibrational Raman modes in ZnO nanocrystals, revealing specific mode shifts and local vibrational features linked to Mn incorporation.

Contribution

It provides detailed analysis of Raman modes in Mn-doped ZnO, identifying new vibrational features associated with Mn doping not previously characterized.

Findings

Identification of Mn-related vibrational mode at 528 cm-1

Assignment of specific Raman modes to ZnO lattice vibrations

Observation of resonance and impurity effects enhancing certain modes

Abstract

Mn-doped ZnO was synthesized using a co-precipitation technique. X-ray diffraction (XRD) measurements and photoluminescence (PL) spectra show that Mn ions are doped into the lattice positions of ZnO. The modes at 202, 330, and 437 cm-1 in the Raman spectrum are assigned as 2E2 (low), E2 (high)-E2 (low), and E2 (high) modes of ZnO base, respectively. The mode at 528 cm-1 is ascribed to a local vibrational mode related to Mn. The mode at 580 cm-1 should be an intrinsic mode of ZnO and assigned to E1 longitudinal optical (LO). Its reinforcement should result from a combination of resonance at the excitation wavelength and impurity-induced scattering.