Dramatically improved electron transport performance by a deep triangular potential well in organic field-effect transistors

Abstract

Overcoming the intrinsic properties of organic molecules to achieve high device performance, particularly for electron transport, is a challenge in the field of organic semiconductor device physics. Energy-band engineering in modern inorganic electronics has been introduced in organic electronics. Here, we utilized Al2O3 and PbO metal-oxide layers as dielectric modification layers and fabricated high-quality organic heterojunction films with large band bending and sharp interfaces. The large band bending indicated a deeper triangular potential well, which can confine more electrons and form a high carrier density organic two-dimensional electron gas. A sharp heterojunction interface can reduce interface carrier transport scattering and crystal lattice defects and can retain uniform interfacial electronic structures. These two features of organic heterojunctions are the key factors to realize energy-band engineering in organic electronics. By using these heterojunction films as active layers in organic field-effect transistors, the transistors exhibited a high electron mobility of approximately 8 cm2 V−1 s−1. Therefore, we demonstrated the feasibility and solutions of energy-band engineering in organic electronics, and provided a novel strategy to improve device performance.