Simultaneously ultrafast and robust two-dimensional flash memory devices based on phase-engineered edge contacts

Abstract As the prevailing non-volatile memory (NVM), flash memory offers mass data storage at high integration density and low cost. However, due to the dilemma of ‘speed-retention-endurance’, their typical operation speed is limited ~microseconds to milliseconds for program and erase, restricting their application in scenarios with high-speed data throughput. Here, by adopting metallic 1T-LixMoS2 as edge contact, we show that ultrafast (10-100 ns) and super-robust (endurance>106 cycles, retention>10 years) memory operation can be simultaneously guaranteed in two-dimensional van der Waals heterostructure flash memory with 2H-MoS2 as semiconductor channel. The superior performance stems from the highly gate tunable Schottky barrier at the edge contact, which facilitates hot carrier injection to semiconductor channel and subsequent tunneling if compared to conventional top contact that has rich defects under metal. Our results show the promise of inventing 2D flash memory via contact engineering to further advance the prevailing flash memory technology to meet for the increasing demand of high speed and reliable data storage.