Photoluminescence Imaging and Electrical Characterization of Defects in van der Waals Materials

Abstract

2D van der Waals materials possess unique optical, electrical, and physical characteristics, leading to their applications in electronics, photonics, and optoelectronics. Hexagonal boron nitride (hBN), an insulating material with a wide and indirect bandgap, features diverse color centers across NIR to UV wavelengths. As a gate dielectric, color centers within hBN increase the device's leakage current, emphasizing the importance of understanding their spatial distribution and influence on the device's conductivity. This study demonstrated that a device with a high density of carbon color centers in hBN exhibited a different tunneling mechanism for current compared to a defect-free hBN device, ultimately revealing that defects reduced the electrical durability of the device. Furthermore, a new platform for material optical analysis was developed by employing machine learning to analyze the photoluminescence (PL) of hBN's color centers and interlayer excitons observed in a WSe2/MoSe2 heterostructure.