Direct growth of hexagonal boron nitride on photonic chips for high-throughput characterization

TL;DR

This paper introduces a novel method for directly growing hexagonal boron nitride on photonic chips, enabling high-throughput defect characterization without transfer-related contamination, and demonstrates its advantages over traditional transfer methods.

Contribution

The paper presents a new direct growth technique for 2D materials on photonic chips, eliminating transfer steps and reducing contamination, with potential extension to other 2D materials.

Findings

Direct growth of hBN on silicon nitride chips is feasible.

Direct growth reduces contamination compared to transfer methods.

The approach enhances the throughput and reliability of defect characterization.

Abstract

Adapting optical microscopy methods for nanoscale characterization of defects in two-dimensional (2D) materials is a vital step for photonic on-chip devices. To increase the analysis throughput, waveguide-based on-chip imaging platforms have been recently developed. Their inherent disadvantage, however, is the necessity to transfer the 2D material from the growth substrate to the imaging chip which introduces contamination, potentially altering the characterization results. Here we present a unique approach to circumvent these shortfalls by directly growing a widely-used 2D material (hexagonal boron nitride, hBN) on silicon nitride chips, and optically characterizing the defects in the intact as-grown material. We compare the direct growth approach to the standard wet transfer method, and confirm the clear advantages of the direct growth. While demonstrated with hBN in the current work, the method is easily extendable to other 2D materials.