Investigation of STM image artifacts by in-situ reflection electron microscopy

Scanning tunneling microscope (STM) image artifacts have been studied using an STM operating inside a transmission electron microscope (TEM). This instrument allows independent imaging of the same region by STM and reflection electron microscopy (REM). Modifications made recently have increased its rigidity. STM atomic resolution imaging of graphite inside the TEM demonstrate its stability. Comparison of STM and REM images of nanometer-scale features have revealed image artifacts caused by the STM tip. In particular, instances where features were broadened by tip convolution have been directly identified. Broadening of objects by up to three times is a common occurrence. We have also found instances where features were compressed by the STM tip while imaging. This results in inaccurate STM height information about the feature. This leads to questions about the accuracy of STM images of nanometer-scale features.