Comparative Analysis of Hg2Br2 and Hg2BrxCl2-x Crystals Grown via PVT

Ojun Kwon,Gun-Eik Jang,Byungjin Cho,Shi-Gwan Woo,Kyoungah Kim

doi:10.3390/cryst10121096

Abstract

In this study, we comparatively analyzed the physical properties of Hg2Br2 and Hg2BrxCl2−x crystals synthesized via physical vapor transport (PVT). Prior to crystal growth, the elemental mapping images obtained through scanning electron microscopy/energy-dispersive spectroscopy clearly showed the presence of Cl atoms (2.62%) in Hg2BrxCl2−x powder; however, Cl atoms were not detected in Hg2Br2 powder. After crystal growth by PVT, each single crystal was characterized using various analysis techniques, such as X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy. It was observed that the introduction of Cl elements into Hg2Br2 crystals strongly affected the crystallinity and Raman vibration modes. Hence, this in-depth material characterization study proposed a feasible method to screen impurities in mercury halide crystals.

Highlights

Acousto-optic tunable filters (AOTFs) are used to rapidly and dynamically select a specific wavelength from a broadband laser source
The raw powder was purified by physical vapor transport (PVT) at 300 ◦ C for 10 h under vacuum, and the chamber was cooled at a slow rate of 1 ◦ C/min to prevent the nucleation of Hg and its related secondary phases
We comparatively investigated crystals grown from different mercury halide powders (Hg2 Br2 and Hg2 Brx Cl2−x )

Summary

Introduction

Acousto-optic tunable filters (AOTFs) are used to rapidly and dynamically select a specific wavelength from a broadband laser source. An AOTF module comprises a piezoelectric transducer and an acousto-optic modulator (AOM) single crystal. The vibration frequency of the piezoelectric transducer determines the diffraction properties of the incident light on the AOM crystal, thereby enabling the diffraction of specific wavelengths. AOTFs are used in a variety of applications, such as medical diagnostics, mineral exploration, air quality monitoring, and the detection of harmful biological agents [1,2,3,4]. AOTFs exhibit excellent performance in selectively identifying toxic aerosols in air. This application of AOTFs must be further studied to effectively detect other toxic substances. AOM crystal materials covering this range should be actively explored [5,6,7]

Methods

Findings

Discussion

Conclusion