Surface doping in T6/ PDI-8CN2 Heterostructures investigated by transport and photoemission measurements

TL;DR

This study investigates surface doping effects in T6/PDI-8CN2 heterostructures using transport and photoemission measurements, revealing band bending and increased conductivity due to interface accumulation heterojunction formation.

Contribution

It provides experimental evidence of surface doping mechanisms in T6 transistors caused by PDI-8CN2 deposition, combining electrical and photoemission data.

Findings

Increased conductivity in T6 transistors due to PDI-8CN2 surface doping

Shift of T6 HOMO peak indicating band bending

Formation of accumulation heterojunction at the interface

Abstract

In this paper, we discuss the surface doping in sexithiophene (T6) organic field-effect transistors by PDI-8CN2. We show that an accumulation heterojunction is formed at the interface between the organic semiconductors and that the consequent band bending in T6 caused by PDI-8CN2 deposition can be addressed as the cause of the surface doping in T6 transistors. Several evidences of this phenomenon have been furnished both by electrical transport and photoemission measurements, namely the increase in the conductivity, the shift of the threshold voltage and the shift of the T6 HOMO peak towards higher binding energies.