Role of sublimation kinetics of ammonia borane in chemical vapor deposition of uniform, large-area hexagonal boron nitride

• Autor(a) principal: Sompalle, Balaji
• Data de Publicação: 2021
• Outros Autores: Liao, Chun-Da, Wei, Bin, Cerqueira, Maria de Fátima, Nicoara, Nicoleta, Wang, Zhongchang, Sadewasser, Sascha, Alpuim, P.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: https://hdl.handle.net/1822/81350
• topic: Engenharia e Tecnologia::Nanotecnologia; Science & Technology

Hexagonal boron nitride (h-BN) is a critical 2D insulator used as a substrate, gate dielectric, or encapsulation layer for graphene and other 2D materials and their van der Waals heterostructures. It is also promising as an active layer in single-photon emitters and other photonic devices. With the chemical formula H3N-BH3, ammonia borane is the most attractive precursor for up-scalable growth of large-area h-BN, using chemical vapor deposition given its stoichiometric B:N ratio, high stability under ambient conditions, nontoxicity, and high solubility in common solvents. Here, the synthesis of large-area (100 × 150 mm2) crystalline hexagonal boron nitride layers by thermal activation and decomposition of the precursor ammonia borane is presented. We describe two different reaction pathways for h-BN synthesis, providing evidence for dissimilarities in the sublimation kinetics of ammonia borane and how these differences critically influence the growth of h-BN. This understanding helps us accelerate h-BN production, reuse precursors, and reduce machine runtime, paving the way for upscalability. Moreover, our work provides a consistent unified view explaining the diverse deposition conditions reported in the literature for h-BN grown by CVD using ammonia borane as a precursor.