Effective N-methyl-2-pyrrolidone wet cleaning for fabricating highperformance monolayer MoS2 transistors

Two-dimensional semiconductors,such as MoS2 are known to be highly susceptible to diverse molecular adsorbates on the surface during fabrication,which could adversely affect device performance.To ensure high device yield,uniformity and performance,the semiconductor industry has long employed wet chemical cleaning strategies to remove undesirable surface contaminations,adsorbates,and native oxides from the surface of Si wafers.A similarly effective surface cleaning technique for two-dimensional materials has not yet been fully developed.In this study,we propose a wet chemical cleaning strategy for MoS2 by using N-methyl-2-pyrrolidone.The cleaning process not only preserves the intrinsic properties of monolayer MoS2,but also significantly improves the performance of monolayer MoS2 field-effect-transistors.Superior device on current of 12 μA·μm-1 for a channel length of 400 nm,contact resistance of 15 kΩ·μm,field-effect mobility of 15.5 cm^2·V^-1·s^-1,and the average on-off current ratio of 10^8 were successfully demonstrated.

Implementing hardware primitives based on memristive spatiotemporal variability into cryptography applications

Implementing hardware primitives into cryptosystem has become a new trend in electronic community.Memristor,with intrinsic stochastic characteristics including the switching voltages,times and energies,as well as the fluctuations of the resistance state over time,could be a naturally good entropy source for cryptographic key generation.In this study,based on kinetic Monte Carlo Simula-tion,multiple Artificial Intelligence techniques,as well as kernel density map and time constant analysis,memristive spatiotemporal variability within graphene based conductive bridging RAM(CBRAM)have been synergistically analyzed to verify the inher-ent randomness of the memristive stochasticity.Moreover,the ran-dom number based on hardware primitives passed the Hamming Distance calculation with high randomness and uniqueness,and has been integrated into a Rivest-Shamir-Adleman(RSA)cryptosystem.The security of the holistic cryptosystem relies both the modular arithmetic algorithm and the intrinsic randomness of the hardware primitive(to be more reliable,the random num-ber could be as large as possible,better larger than 2048 bits as NIST suggested).The spatiotemporal-variability-based random number is highly random,physically unpredictable and machinelearningattack resilient,improving the robustness of the entire cryptosystem.