Negative Differential Resistance Transistor with Organic p‐n Heterojunction

Abstract

Negative differential resistance (NDR) has large potential for versatile device applications, including high‐frequency oscillators, memories, fast switches, and multilevel logic circuits. NDRs are observed at heteromaterial interfaces in resonant tunneling diodes or Esaki diodes consisting of compound semiconductors or two‐dimensional (2D) atomic thin films. However, these devices suffer from poor peak‐to‐valley ratios (PVR) at room temperature; a cryogenic temperature is needed to improve the PVR. These negative factors are obstacles to practical applications. Here, a new NDR transistor is proposed, in which a p‐n heterojunction of organic semiconductors plays a key role. Well‐balanced carrier transport is manipulated at the organic p‐n junction to realize outstanding NDR. Experimental and simulation analyses reveal that the observed NDR can be explained by analogy with the shoot‐through current mechanism in complementary metal‐oxide‐ semiconductor (CMOS) devices. As a result, the NDR transistor shows large PVRs of up to about 10 4 even at room temperature.