Silicon-integrated diodes made with solution-processed 2D materials

Printed electronics based on two-dimensional (2D) materials provides a scalable and low-cost approach to device fabrication, enabling mask-free patterning and low-temperature processing. Among additive techniques, inkjet printing is particularly attractive due to its digitally programmable deposition and minimal material waste. Furthermore, inkjet printing of 2D materials offers a viable route for integration with established silicon technologies, providing a transfer-free and back-end-of-line (BEOL)-compatible pathway for hybrid device architectures. The first demonstrations of inkjet printed graphene-silicon diodes proved the viability of solution-processed nanosheets/Si junctions. However, because of the intrinsic nature of the Schottky architecture, these devices inherently exhibited relatively high reverse currents and limited barrier tunability. In this work, to address these limitations, we report the fabrication of metal-insulator-semiconductor (MIS) diodes by inkjet-printing a solution-processed MoS2 insulating layer between graphene and n-type silicon. The presence of the additional insulating layer enables suppressed leakage current and thickness-controlled rectification. We compare the performance of devices realized on mechanically scratched and cleanroom-patterned silicon substrates. In both cases, the MIS diodes exhibit clear rectifying behaviour and low reverse leakage. However, only the devices fabricated on chemically patterned substrates enable systematic tuning of performance through control of the insulating layer thickness. Our work demonstrates that printed graphene-MoS2-Si junctions enable to fabricate diodes, within a fully BEOL-compatible process, with very good rectification ( ∼ 106) and ideality factor (1.3).