Band Alignment at Molybdenum Disulphide/Boron Nitride/Aluminum Oxide Interfaces

To facilitate the design of future heterostructure devices employing two-dimensional (2D) materials such as molybdenum disulphide (MoS₂) and hexagonal/sp² boron nitride (BN), x-ray photoelectron spectroscopy (XPS) has been utilized to determine the valence band offset (VBO) present at interfaces formed between these materials. For MoS₂ grown on a pulsed laser-deposited amorphous BN (a-BN) layer with sp² bonding, the VBO was determined to be 1.4 ± 0.2 eV. Similarly, the VBO between the a-BN layer and the aluminum oxide (Al₂O₃) substrate was determined to be 1.1 ± 0.2 eV. Using the bandgaps established in the literature for MoS₂, h-BN, and Al₂O₃, the conduction band offsets (CBOs) at the MoS₂/a-BN and a-BN/Al₂O₃ interfaces were additionally calculated to be 3.3 ± 0.2 and 1.7 ± 0.2 eV, respectively. The resulting large VBOs and CBOs indicate BN and Al₂O₃ are attractive gate dielectrics and substrates for future 2D MoS₂ devices.