Advances in the nanotechnology, which is still in its infancy, will depend on our ability todesign, build, replicate, and mass-produce usable nanoscale systems. At sub-nanometer lengthscales, scanning tunneling microscopy (STM) and the related techniques, collectively calledscanning probe microscopies, replace the optical microscopy for real-space imaging andmanipulation of materials. STM
... [Show full abstract] operation is based on measurement of current due to tunnelingof electrons across a finite potential barrier between the probe and the sample. In conventionalSTM, tunneling current of tens of nA and probe-sample distance of a few Å are maintained.These conditions, while necessary for atomic-scale imaging under ultra high vacuum environment,are not suited to handle nanostructures. Quantum structures deposited on a flat substrate usuallypresent a non-metallic sample, and the roughness levels involved are much too high forconventional STM. STM operation with low tunneling current (few pA) and larger tunneling gap(several nm) is preferred to overcome these difficulties. This paper presents experimental workand theoretical considerations for developing an atmospheric low-current STM (LC-STM).Researchers from diverse fields can build their own LC-STM for routine imaging and spectroscopy.Several design details are included keeping this aspect in mind.