Hexagon Flower Quantum Dot-like Cu Pattern Formation during Low-Pressure Chemical Vapor Deposited Graphene Growth on a Liquid Cu/W Substrate.

Phuong V Pham

doi:10.1021/acsomega.8b00985

Abstract

The H2-induced etching of low-dimensional materials is of significant interest for controlled architecture design of crystalline materials at the micro- and nanoscale. This principle is applied to the thinnest crystalline etchant, graphene. In this study, by using a high H2 concentration, the etched hexagonal holes of copper quantum dots (Cu QDs) were formed and embedded into the large-scale graphene region by low-pressure chemical vapor deposition on a liquid Cu/W surface. With this procedure, the hexagon flower-etched Cu patterns were formed in a H2 environment at a higher melting temperature of Cu foil (1090 °C). The etching into the large-scale graphene was confirmed by optical microscopy, atomic force microscopy, scanning electron microscopy, and Raman analysis. This first observation could be an intriguing case for the fundamental study of low-dimensional material etching during chemical vapor deposition growth; moreover, it may supply a simple approach for the controlled etching/growth. In addition, it could be significant in the fabrication of controllable etched structures based on Cu QD patterns for nanoelectronic devices as well as in-plane heterostructures on other low-dimensional materials in the near future.

Highlights

Graphene, a honeycomb crystal carbon lattice, has attracted huge research interest during the past few years due to its anomalous properties, including very high carrier mobility, extremely high mechanical strength and optical transparency, electrical conductivity, etc.[1−25] As a result, graphene is considered to be an ideal nanomaterial for next-generation semiconductors to replace silicon.The etching of material is the block removal from a material matrix by chemical or physical methods the reverse of the growth process
Low-pressure chemical vapor deposition (LPCVD) is investigated at low pressure (6 Torr) using Cu as a catalytic substrate located on a W foil
The integrated etching/growth proceeded via the LPCVD approach with hexagon flower-etched

Summary

■ INTRODUCTION

A honeycomb crystal carbon lattice, has attracted huge research interest during the past few years due to its anomalous properties, including very high carrier mobility, extremely high mechanical strength and optical transparency, electrical conductivity, etc.[1−25] As a result, graphene is considered to be an ideal nanomaterial for next-generation semiconductors to replace silicon. Material growth/etching requires a high-energy barrier nucleation process. The material growth systems have been controlled with different scales (nanometer to micrometer).[26−28] The family of snow-crystal-like graphene with patterns is formed by a nonlinear process in nature.[29] In contrast, the highly crystalline materials (e.g., Si) are etched via an anisotropic rule,[30] leading to stable etched patterns with Euclidean geometries. The high crystal C atom single-layer supplies a simple model to study the fundamental growth and/or etching process via the chemical vapor deposition (CVD) method. Several reports on graphene etching have been carried out and utilizing metallic various etchants, nanoparticles.[41−43] such as plasma H2,35−38 Recently, graphene crystal. The hexagon quantum dot (QD)-like etched Cu pattern is a new morphology that has not yet been revealed

■ RESULTS AND DISCUSSION

■ CONCLUSIONS

■ REFERENCES