Precise Determination of the Crystallographic Orientations in Single ZnS Nanowires by Second-Harmonic Generation Microscopy

TL;DR

This paper demonstrates a precise, non-destructive method using second-harmonic generation microscopy to determine the crystallographic orientations of individual ZnS nanowires, with implications for nanoscale optical applications.

Contribution

The study introduces a SHG microscopy technique for accurate orientation determination of single ZnS nanowires, revealing their crystal axes with high sensitivity.

Findings

SHG response varies with nanowire orientation

All three crystal axes of ZnS NWs are precisely identified

High SHG conversion efficiency of 7×10^(-6) achieved

Abstract

We report on the systematical study of the second-harmonic generation (SHG) in single zinc sulfide nanowires (ZnS NWs). The high quality ZnS NWs with round cross-section were fabricated by chemical vapor deposition method. The transmission electron microscopy images show that the actual growth-axis has a deviation angle of 0o~20o with the preferential growth direction [120], which leads to the various polarization-dependent SHG response patterns in different individual ZnS NWs. The SHG response is quite sensitive to the orientations of c-axis as well as the (100) and (010) crystal-axis of ZnS NWs, thus all the three crystal-axis orientations of ZnS NWs are precisely determined by the SHG method. A high SHG conversion efficiency of 7*10^(-6) is obtained in single ZnS NWs, which shows potential applications in nanoscale ultraviolet light source, nonlinear optical microscopy and nanophotonic devices.