Cold Source Diodes With Sub-Unity Ideality Factor and Giant Negative Differential Resistance

Conventional Schottky diodes have a switching limit of ideality factor larger than unity due to the thermionic emission. In this work, cold source diodes (CSDs) using cold metals of monolayer 2H phase MX2(M = Nb, Ta; X = S, Se) as the injection source are proposed and investigated by first-principles quantum transport simulations. Different from the conventional Schottky diode, CSDs can break the ideality factor limit of unity and reach steep switching. Cold metals such as 2H MX(2)are metallic but have energy gaps around the Fermi level. Therefore, high-energy electrons can be effectively filtered and the leakage current is suppressed at off-state. It is shown that the ideality factor of CSDs can be smaller than 1 over eight decades with a minimum of 0.17. At the same time, giant negative differential resistance is realized in CSDs and the peak-to-valleyratio (PVR) can be over 10(6) with a peak current over 100 mu A/mu m.

Automated summary

In this study, a new type of cold source diode (CSDs) is proposed and investigated, which can break the limit of the ideality factor in conventional Schottky diodes and achieve steep switching. CSDs use cold metals of monolayer 2H phase MX2 with energy gaps as the injection source, effectively filtering high-energy electrons and suppressing leakage current.