Carbon nanotube columns each comprising carbon nanotubes can be utilized as electrically conductive contact probes. The columns can be grown, and parameters of a process for growing the columns can be varied while the columns grow to vary mechanical characteristics of the columns along the growth length of the columns. Metal can then be deposited inside and/or on the outside of the columns, which can enhance the electrical conductivity of the columns. The metalized columns can be coupled to terminals of a wiring substrate. Contact tips can be formed at or attached to ends of the columns. The wiring substrate can be combined with other electronic components to form an electrical apparatus in which the carbon nanotube columns can function as contact probes.