Gold Coated Tungsten Tips for Scanning Tunneling Microscopy

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Review of Scientific Instruments and may be found at https://doi.org/10.1063/1.1144069.Electrochemically etched tungsten scanning tunneling microscope (STM) tips are dc sputter coated with 20 nm of gold (0.04 rim/s and 10 mTorr of argon). Transmission electron microscope (TEM) images of typical etched tips and gold-coated etched tips are presented. The gold layer forms as a series of spherical sections having a mean height of 6.7 nm and mean width of 19.6 nm. STM images are reported for the uncoated W tips, and for gold-coated graphite after coating the tip with gold. We also provide scanning electron microscopy (SEM) and STM images of the surface of a thin CuTCNQ film. The STM image taken with a gold-coated W tip compares very well to the SEM image of the same sample. Gold coating provides a relatively inexpensive and easy way to produce chemically stable tips of well known electronic structure for use in ambient atmosphere STM studies of morphology (structures ) 10 nm) where atomic resolution is not required.G.A. Fried, X.D. Wang, and K.W. Hipps. (1993). Gold Coated Tungsten Tips for Scanning Tunneling Microscopy. Review of Scientific Instruments. 64. 1495-1501