2025/10/08 by Sungjae Hong, Aaron J. Muhowski, Victor J. Patel +2 · 1 voice
Engineering · Physics and Astronomy · #Advancements in Semiconductor Devices and Circuit Design #Semiconductor Quantum Structures and Devices #Semiconductor materials and devices
paper · doi:10.1063/5.0289403
openalex publication_date 2025/10/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
Negative differential resistance (NDR), where the device current decreases with increasing bias voltage, is a representative phenomenon where quantum mechanics induces counterintuitive physical behavior and offers promising applications such as high-frequency oscillators, amplifiers, and multilevel logic circuits. While the NDR behavior has been extensively studied in various materials and devices, the role of surface properties in NDR, particularly in InAs-based diodes, remains underexplored. In this work, we report the observation of NDR in vertically structured InAs p+n diodes that exhibit a peak-valley current ratio of ∼6, which is suitably high for applications. Circumference-normalized current–voltage characterization revealed that the NDR originates from band-to-band tunneling between the valence band of p+-InAs and the conduction band of an n+-InAs surface, where the n+ surface is due to surface states on otherwise n−-InAs. In addition, by comparing devices with various surface passivation methods (without intentional passivation, benzocyclobutene polymer, and silicon nitride), we found that the surface termination significantly affects the NDR characteristics. We present an equivalent circuit model to explain the observed device behavior. These findings offer insights into surface-enabled NDR phenomena and present new knobs for engineering NDR devices.