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.