A VERSATILE MICROWAVE-FREQUENCY-COMPATIBLE SCANNING TUNNELING MICROSCOPE

Challenged by the need to transmit a microwave frequency signal to and from the tunnel junction of a scanning tunneling microscope (STM), an STM has been designed and built that provides minimal microwave signa l loss. The STM has been operated over a wide frequency range, dc to 2 0 GHz, without the use of a microwave resonance cavity. This design al so provides a flexible feedback scheme allowing selection of the requi red piezoelectric gain and stability. A reliable, easy to fabricate sa mple approach is also described that adds to the stability of this des ign. The operation of this microscope by imaging a lead silicate glass surface with a bias voltage modulation frequency and detection freque ncy of 7.73 GHz is demonstrated.