Understanding the local electronic properties of ZrTe2

Abstract

TMDCs (Transition Metal DiChalcogenides) have garnered significant attention due to their exceptional optical, electronic, & topological properties. Among them, zirconium ditelluride (ZrTe2) stands out for its semimetallic nature, strong spin-orbit coupling, and potential topological states. However, its susceptibility to oxidation presents both challenges and opportunities for device applications. This thesis provides a detailed investigation into the oxidation dynamics of ZrTe2, alongside its structural, surface, and electronic properties. A comprehensive study of ZrTe2 oxidation was conducted using Atomic force microscopy (AFM), High-Resolution Transmission electron microscopy (HRTEM), and Raman spectroscopy. These analyses revealed that oxidation predominantly initiates at the edges and surfaces, leading to the formation of amorphous ZrO2 and tellurium aggregation. This transformation significantly alters the electronic properties of ZrTe2, impacting its potential applications in nanoelectronics. Given that ZrO2 is a high-dielectric (κ = 25) material widely used in MOSFETs, understanding this oxidation process is critical for the controlled integration of ZrTe2 into electronic devices. Additionally, the rapid and spontaneous oxidation behavior suggests potential use in low-cost oxygen sensors. To complement these findings, STM and spectroscopy (TSS) were employed to investigate the atomic-scale surface and electronic properties of ZrTe2 and its derivative ZrSeTe. Ultrahigh vacuum low-temperature STM (UHV LT-STM) measurements provided insights into the surface, the density of states, and electronic band structures. The experimental observations were compared with theoretical predictions from density functional theory (DFT). These insights offer a pathway for the controlled utilization of ZrTe2 in future electronic, sensing, and quantum device applications.