Edge-Dependent Step-Flow Growth Mechanism in β-GaO (100) Facet at the Atomic Level.

Journal: The journal of physical chemistry letters
Published Date: May 22, 2025

Abstract

Homoepitaxial step-flow growth of high-quality β-GaO thin films is essential for the advancement of high-performance GaO-based devices. In this work, the step-flow growth mechanism of the β-GaO (100) facet is explored by machine-learning molecular dynamics simulations and density functional theory calculations. Our results reveal that Ga adatoms and Ga-O adatom pairs, with their high mobility, are the primary atomic species responsible for efficient surface migration on the (100) facet. The asymmetric monoclinic structure of β-GaO induces a distinct two-stage Ehrlich-Schwoebel barrier for Ga adatoms at the [00-1] step edge, contributing to the suppression of double-step and hillock formation. Furthermore, a miscut toward [00-1] does not induce the nucleation of stable twin boundaries, whereas a miscut toward [001] leads to the spontaneous formation of twin boundaries. This research provides meaningful insights not only for high-quality β-GaO homoepitaxy but also the step-flow growth mechanism of other similar systems.

Authors

  • Qi Li
    The First Affiliated Hospital of Yangtze University, Jingzhou, Hubei, China.
  • Junlei Zhao
    Department of Electronic and Electrical Engineering, Southern University of Science and Technology, Shenzhen, 518055 China.
  • Na Lin
    Affiliated Hospital of Youjiang Medical University for Nationalities, Department of Pediatrics, Baise, PR China. Electronic address: jxee18@163.com.
  • Xiufeng Cheng
    State Key Laboratory of Crystal Materials, Institute of Novel Semiconductors, Institute of Crystal materials, Shandong University, Jinan, Shandong 250100, China.
  • Xian Zhao
    College of Information Engineering, Shanghai Maritime University, Shanghai 201306, China.
  • Zhaojun Liu
    Department of Neurology, The Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang Province, China.
  • Zhitai Jia
    State Key Laboratory of Crystal Materials, Institute of Novel Semiconductors, Institute of Crystal materials, Shandong University, Jinan, Shandong 250100, China.
  • Mengyuan Hua
    Department of Electronic and Electrical Engineering, Southern University of Science and Technology, Shenzhen, 518055 China.

Keywords

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