Synthesis of MoS 2 Layers on GaN Using Ammonium Tetrathiomolybdate for Heterojunction Device Applications

• Published in: Crystal research and technology (1979) 2021-06, Vol.56 (6)
• Main Authors: Desai, Pradeep, Todankar, Bhagyashri, Ranade, Ajinkya K., Kondo, Masaharu, Dewa, Takehisa, Tanemura, Masaki, Kalita, Golap
• Format: Article
• Language: English
• ISSN: 0232-1300; 1521-4079
• DOI: 10.1002/crat.202000198

2D materials such as molybdenum sulfide (MoS 2 ) integrated with conventional semiconductors lead to the fabrication of novel heterojunctions with pivotal electrical and optoelectronic properties. Herein, an approach is reported which addresses the growth of MoS 2 crystals on the lattice‐matched Ga–polar gallium nitride (GaN) wafer using ammonium tetrathiomolybdate (ATM) as a precursor in a chemical vapor deposition (CVD) process, instead of using the molybdenum‐oxide‐based precursors. Unidirectional triangular MoS 2 crystals and continuous film are obtained on the free‐standing Ga–polar GaN substrate. Further, the interface quality of the as‐synthesized MoS 2 crystals and GaN wafer is explored by X‐ray photoelectron spectroscopy. It is observed that a good quality interface can be obtained by using the ammonia‐containing ATM precursor, where the surface oxygen at the interface is significantly less. A heterojunction device is fabricated with the synthesized MoS 2 layer on GaN, showing excellent rectifying diode characteristics and a photovoltaic action with light illumination. This study reveals the suitability of the ammonia‐containing ATM precursor for the growth of MoS 2 crystals on GaN in the CVD process to obtain a suitable heterostructure for device applications.