A Simple, Compact and Rigid Scanning Tunneling Microscope

We present a homebuilt scanning tunneling microscope (STM) which employs an inner-wall polished sapphire guiding tube as a rail for the scanner to form a short tip-sample mechanical loop. The scanner is mounted on a square rod which is housed in the guiding tube and held by a spring strip. The stiff sapphire guiding tube allows the STM body to be made in a simple, compact and rigid form. Also the material of sapphire improves the thermal stability of the STM for its good thermal conductivity. To demonstrate the performance of the STM, high quality atomic-resolution STM images of high oriented pyrolytic graphite were given.