Characterization of Chemistry and Physics at Metal-Polythiophene and Metal-Carbon Interfaces
EMSL Project ID
19830
Abstract
We propose to use photoemission techniques to investigate the chemistry and physics that govern electrical properties at metal-semiconductor interfaces that have a potential for future energy applications. The semiconductor films will be one of two types: 1) an organic polymer (specifically, polythiophene) or 2) nanostructured carbons. Because all electronic devices require conductive contacts, it is essential to understand the fundamental mechanisms that control the electrical properties at these interfaces. As described in the proposal, both material types have potential applications for renewable energy in the form of photovoltaics. As such, we believe that this research fits well within EMSLs mission to support the needs of DOE and the nation. More specifically, this proposal addresses the EMSL Science Theme "Science of Interfacial Phenomena" via its emphasis on atomic/molecular level understanding of interfacial chemistry and physics and their relationship to the electrical transport properties.
The development of the potential devices from the materials in both projects relies on an understanding of how to fabricate ohmic and rectifying contacts to the films. We are currently developing process methods at Carnegie Mellon and measuring the electrical properties of the films/contacts. To understand how to control the contact characteristics, however, it will be important to understand the interfacial chemistry and physics (e.g., Schottky barrier heights). As such, we propose to employ photoemission techniques (e.g., Auger electron spectroscopy, x-ray photoelectron spectroscopy, and ultraviolet photoelectron spectroscopy) at EMSL to study the interfacial chemistry and physics of selected metal/semiconductor samples. Metals and compounds have been selected based on various properties, such as workfunctions, resistivities, and chemistries with the semiconductor films. Photoemission characterization will allow us to measure barrier heights and to understand how the interfacial chemistry affects the electrical properties (e.g., the workfunction-barrier height relationships) of working devices.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2006-08-01
End Date
2009-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Singh A, T Nelson, J Belot, T Young, NR Dhumal, T Kowalewski, RD McCullough, P Nachimuthu, S Thevuthasan, and LM Porter. 2011. "Effect of Self-Assembled Monolayers on Charge Injection and Transport in Poly(3-hexylthiophene) based Field-Effect Transistors at Different Length Scales." PNNL-SA-78076, Pacific Northwest National Laboratory, Richland, WA. [Unpublished]