Fig. 1. (A) An STM topography scan of Ti0.87O2 nanosheets on Pt(200 nm)/Si of an area of 0.83 um × 0.83 um. Only a faint contrast is observed due to the presence of the nanosheets. (B) di/dz map of the same area from (A). A large contrast in the image reflects a larger difference in di/dz on the nanosheet and Pt/Si surface. Here, tunneling current is 0.5 nA and sample bias voltage is +2.5 V.
RHK Technology UHV 7000
RHK Technology SPM 1000 Control System
Avijit Kumara, Suresh Kumar C. Palanisamyb, Jelmer M. Botera, Chris Hellenthala, Johan E. ten Elshofb, Harold J.W. Zandvlieta
aPhysics of Interfaces and Nanomaterials, MESA+Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
bInorganic Materials Science, MESA+Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
Applied Surface Science 265 (2013) 201– 204
We report scanning tunneling microscopy (STM) and spectroscopy (STS) measurements on single layer Ti0.87O2 nanosheets deposited on Pt(200 nm)/Si substrates. These nanosheets have a band gap of 3.8 eV and are virtually invisible in conventional STM images. However, an impressive contrast is observed in the di/dz map, which allows for a clear identification of the nanosheets. The di/dz signal is obtained by adding a high frequency, small amplitude modulation to the z-piezo using a lock-in amplifier.