A versatile variable-temperature scanning tunneling microscope for molecular growth.

We describe and discuss the design of a variable-temperature scanning tunneling microscope (STM) system for the study of molecules at temperatures between 18 and 300 K in ultrahigh vacuum. The STM head is a refinement of a very rigid design developed and successfully operated in Hamburg. In the current version, the head is connected to a liquid helium flow cryostat, thereby reaching a base temperature of 18 K.