Role of Molecular Surface Passivation in Electrical Transport Properties of InAs Nanowires

• Published in: Nano letters Vol. 8; no. 1; pp. 49 - 55
• Main Authors: Hang, Qingling, Wang, Fudong, Carpenter, Patrick D, Zemlyanov, Dmitri, Zakharov, Dmitri, Stach, Eric A, Buhro, William E, Janes, David B
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-01-2008
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic structure of nanoscale materials : clusters, nanoparticles, nanotubes, and nanocrystals; Electronics; Exact sciences and technology; Materials science; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Transistors; Conduction bands; Density of states; Electronic properties; Transport properties; Electrical properties; Field effect transistors; Digital simulation; Indium arsenides; Thin films; Interfaces; Electron traps; Electronic structure; Fermi level; Electron state; Electron mobility; Nanowires; Nanostructured materials; Quantitative chemical analysis; Electron donor; III-V semiconductors; X-ray photoelectron spectra
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl071888t

The existence of large densities of surface states on InAs pins the surface Fermi level above the conduction band and also degrades the electron mobility in thin films and nanowires. Field effect transistors have been fabricated and characterized in the “as fabricated” state and after surface passivation with 1-octadecanethiol (ODT). Electrical characterization of the transistors shows that the subthreshold slope and electron mobility in devices passivated with ODT are superior to the respective values in unpassivated devices. An X-ray photoelectron spectroscopy study of ODT passivated undoped InAs nanowires indicates that sulfur from ODT is bonded to In on the InAs nanowires. Simulations using a two-dimensional device simulator (MEDICI) show that the improvements in device performance after ODT passivation can be quantified in terms of a decrease of interface trap electron donor states, shifts in fixed interfacial charge, and changes in body and surface mobilities.