Title of Paper:Direct Growth of Polycrystalline GaN Porous Layer with Rich Nitrogen Vacancies: Application to Catalyst-Free Electrochemical Detection

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Date of Publication:2021-03-05

Journal:ACS APPLIED MATERIALS & INTERFACES

Volume:12

Issue:48

Page Number:53807-53815

ISSN No.:1944-8244

Key Words:gallium nitride; N-vacancy; electrochemical sensor; electrical conductivity; H2O2 detection

Abstract:It has been demonstrated that defect engineering is an effective strategy to enhance the activity of materials. Herein, a polycrystalline GaN porous layer (PGP) with high catalytic activity was grown by self-assembly on GaN-coated sapphire substrate by using low-temperature (LT) MOCVD growth. Without doping, LT growth can significantly improve the activity and electrical conductivity of PGP, owing to the presence of rich N-vacancies (similar to 10(20) cm(-3)). Identification of rich N-vacancies in the PGP material was realized by using atomically resolved STEM (AR-STEM) characterization. The optimized PGP was applied to catalyst-free electrochemical detection of H2O2 with a limit of detection (LOD) of 50 nM, a fast response speed of 3 s, a wide linear detection range (50 nM to 12 mM), and a high stability. The LOD is exceeding 40 fold lower than that of reported metal-catalyst decorated GaN. Moreover, a quantitative relationship between the sensing performances and N-vacancy of PGP was established. To our knowledge, it is the first time that intrinsic GaN materials can exhibit high catalytic activity.