Field emission behavior of photolithography-based patterned carbon nanotubes (PP-CNTs) was irreversibly degraded, showing a gradual turn-on voltage shift to the high voltage region as a result of field emission measurements. The PP-CNTs show a flat region in Fowler-Nordheim (F-N) plots, which can be attributed to residue-induced emission suppression. The observed degradation in field emission can be attributed to a subsequent degradation of carbon nanotubes emitters by a combination of the high electric-field-induced straightening out effect and the high current-induced burning of PP-CNTs. The local emission current and the stability of electron emission were observed in an attempt to investigate the residue effect of the PP-CNTs on the field emission behavior. (C) 2002 Elsevier Science B.V. All rights reserved.