Systematic Study of Fermi‐Level Pinning at Crystalline Metal/GaN Interfaces: First‐Principles Calculations and Diode Characterization

ABSTRACT The Schottky barrier height (SBH), which serves as a pivotal determinant of charge carrier injection efficiency in electronic devices, critically governs electrical behavior at metal/semiconductor interfaces. However, pronounced metal‐induced gap states at metal contact interfaces induce Fermi‐level pinning, which constrains the controllability of the SBH and ultimately degrades device performance. In this work, atomic models of metal/GaN interfaces with diverse metal terminations are constructed on the basis of first‐principles calculations. The interfacial electrical properties, including binding energies, charge density differences, and SBHs, are systematically investigated. The computational SBH results are further validated using the experimental current‒voltage characteristics of fabricated metal‒GaN Schottky diodes. For n‐type SBHs of different metals, these calculation results reveal a robust linear correlation with metal work functions, yielding a moderate pinning factor ( S ≈ 0.31) that aligns closely with experimental and empirical values. These findings establish a theoretical foundation for SBH engineering at metal/GaN interfaces and offer valuable insights for the design of high‐performance GaN‐based devices.