Columns comprising a plurality of vertically aligned carbon nanotubes can be configured as electromechanical contact structures or probes. The columns can be grown on a sacrificial substrate and transferred to a product substrate, or the columns can be grown on the product substrate. The columns can be treated to enhance mechanical properties such as stiffness, electrical properties such as electrical conductivity, and/or physical contact characteristics. The columns can be mechanically tuned to have predetermined spring properties. The columns can be used as electromechanical probes, for example, to contact and test electronic devices such as semiconductor dies, and the columns can make unique marks on terminals of the electronic devices.