Probing Occupied States of the Molecular Layer in Au−Alkanedithiol−GaAs Diodes

Abstract

Internal photoemission (IPE) studies were performed on molecular diodes in which the alkanedithiol [HS(CH(2))(n)SH, n = 8, 10] molecular layer is sandwiched between Au and GaAs electrodes. The results are compared to those from Au-GaAs Schottky diodes. An exponential energy dependence in the IPE yield was observed for the molecular diodes, in contrast to the quadratic energy dependence characteristic of metal-semiconductor Schottky diodes, indicating that Au is not the source of electrons in the IPE process in the molecular diodes. From the GaAs dopant density dependence, we also can rule out GaAs being the source of these electrons. Compared with the results of cluster electronic structure calculations, we suggest that IPE is probing the occupied levels of GaAs-molecular interfacial states.

Electrical conduction through single molecules and self-assembled monolayers

“…However, nTP is a purely additive printing technique based on the surface chemistry of the appointed surface, which bonds chemically with the metallic layer at the stamp. By bringing the stamp with the thin evaporated metallic layer in contact with the substrate, the metallic layer is chemically bonded to the substrate and released from the stamp, resulting in highly reproducible and well-defined structures with nanometer resolution over large areas [115][116][117]. The most common material used for the elastomeric stamps is poly(dimethylsiloxane) (PDMS).…”

Barrier modification of Au/n-GaAs Schottky structure by organic interlayer

“…Hence, any modification on the interface can change the diode properties. Integrating organic molecules with semiconductors has opened wide opportunities in many areas of bioengineering, sensing, etc., which are difficult to achieve by either one alone [1]. In this context, modification of M-S contacts by organic molecules is noteworthy [2].…”

“…Considerable reports are found on the organic modification in GaAs-based Schottky diodes [1,[17][18][19][20]. Gavrila et al [21] have reported a barrier enhancement of 0.3 eV with DiMePTCDI interlayers on S-GaAs(100).…”

Silicon/organic hybrid heterojunction infrared photodetector operating in the telecom regime

“…8) cannot be decided. However, a similar process for sub-bandgap photoresponse for organic modified GaAs Schottky diodes via an intermediate occupied localized state is proposed by Hsu et al [33] and is extensively reviewed in Ref. [34] (referred therein as a pseudo internal photoemission process).…”