Pulickel M. Ajayan

Visualization of Electron Transport in 2D Semiconductor Heterojunctions

Transfer of electrons through semiconductor heterojunctions is the key process in modern electronics. We have visualized dynamics of electrons in InSe/GaAs through time and spectrally-resolved photoemission electron microscopy, which provides insight to this fundamental operating phenomenon.

Current Rectification by As-Grown Chemical Vapor Deposited Single-Walled Carbon Nanotubes

Observation of diode-like current (I) - voltage (V) characteristics of switches fabricated from chemical vapor deposited (CVD) as-grown single-walled carbon nanotube (SWNT) bundles are presented. Atomic force microscopic analysis of the device structure and surface topology of SWNT suggest the observed rectification of current to possibly result from (a) cross-tube junctions, (b) a mixture of metallic and semiconducting tubes in the SWNT bundles, and/or (c) chirality change along a single tube. The exact mechanism underlying the observed rectification could not be established. The diode-like behavior of SWNT devices discovered in this research opens up new applications of SWNTs as nanoscale AC-DC converter.