First-principal insight of the gold-metal interaction to bilayer MoSe2 of AB and AA stacking order

Abstract

The two-dimensional (2D) bilayer (2L) semiconductors are interesting for next-generation electronic device applications due to their additional degree of freedom such as stacking order. However, the report on the interaction of metals to the 2L semiconductor of different stacking orders is not reported yet. Here, we compare the interaction of gold (Au) metal to 2L-MoSe2 of AB and AA stacking order using density functional theory (DFT) calculations. In 2L-MoSe2, the most stable structures have the 2H and the 3R phases, which corresponds to the AB and AA stacking order. To unveil the nature of the interaction between Au and 2L- (AB and AA) MoSe2 semiconductor, the Schottky barrier height (ΦSB, n), tunnel barrier (ΦTB, n), and orbital overlap are calculated. We find that due to significantly enhanced carrier injection (lower ΦSB, n, and ΦTB, n), and higher orbital overlap, the Au/2L-AA MoSe2 resulted as a better alternative, compared to Au/2L-AB MoSe2. The findings provide theoretical guidance for the selection of stacking order for 2L materials for high-performance 2D-electronic devices.