Small gap semiconducting organic charge-transfer interfaces

TL;DR

This study explores the transport properties of organic heterointerfaces formed by single-crystal donor-acceptor molecules, revealing small gap semiconducting behavior with potential implications for electronic applications.

Contribution

It demonstrates that organic heterointerfaces between TMTSF and TCNQ exhibit small gap semiconducting properties, advancing understanding of charge transfer in single-crystal organic systems.

Findings

Interface resistivity of a few tens of MegaOhm

Temperature dependence characteristic of small gap semiconductors

Charge transfer explains transport behavior

Abstract

We investigated transport properties of organic heterointerfaces formed by single-crystals of two organic donor-acceptor molecules, tetramethyltetraselenafulvalene (TMTSF) and 7,7,8,8-tetracyanoquinodimethane (TCNQ). Whereas the individual crystals have un-measurably high resistance, the interface exhibits a resistivity of few tens of MegaOhm with a temperature dependence characteristic of a small gap semiconductor. We analyze the transport properties based on a simple band-diagram that naturally accounts for our observations in terms of charge transfer between two crystals. Together with the recently discovered tetrathiafulvalene (TTF)-TCNQ interfaces, these results indicate that single-crystal organic heterostructures create new electronic systems with properties relevant to both fundamental and applied fields.