Measurement of the light emission spectrum from a scanning tunneling micros
cope (STM) requires a long exposure time due to its extremely low intensity
, and thermal drift of the tip during the exposure time limits the spatial
resolution. To improve the resolution, a computer controlled servomechanism
that locks the STM tip over a target position has been developed. We have
measured the light emission spectra from individual nanometer scale structu
res on an evaporated Au film with and without this mechanism, and demonstra
ted the effectiveness of the servomechanism. (C) 2000 American Institute of
Physics. [S0034-6748(00)01702-0].