Since the beginning of the 21st century, Scanning Probe Microscopy (SPM) has played an increasingly important role in the fields of micro- and nanoscale surface characterization, physical property measurement, and micro/nano fabrication. To provide a more stable operating environment and higher energy resolution for SPM, researchers have developed Low-Temperature Scanning Probe Microscopy (LT-SPM) systems that operate under ultra-high vacuum and low temperature conditions. Currently, most LT-SPM systems achieve temperatures around 4.2 K by supplying liquid helium-4 ( ⁴He) to continuous flow cryostats or low-temperature Dewars. However, due to the low natural abundance of ⁴He and its rising demand, the price of liquid helium has surged dramatically, severely impacting the normal operation of ⁴He-based low temperature equipment. To address this issue, dry (cryogen-free) refrigeration technology has emerged as a promising alternative for next-generation low-temperature systems. In this context, the integration of dry refrigeration technology with SPM to construct DRY-LT-SPM systems has become a key research focus in the field of scanning probe instruments.
This paper mainly discusses several reported closed-cycle DRY -LT-SPM systems, focusing on aspects such as system design, refrigeration schemes, vibration reduction methods, and overall performance. Finally, the paper summarizes the current challenges and issues faced by DRY -LT-SPM systems and explores potential future developments in this field.