Field electron emission (FE) properties of boron and nitrogen doped carbon nanotubes (CNTs) grown in situ on tungsten (W) tips and silicon substrates have been studied. For a total emission current of I mu A, the current density (J) was 4 A/cm(2) at 368 V/mu m for B-doped CNTs and at 320 V/mu m for N-doped CNTs grown on W tips, compared with the value of 1.5 A/cm(2) at 290 V/mu m for undoped CNTs. FE currents upto 400 mu A drawn from both B- and N-doped CNTs are stable for more than 3 h. (c) 2006 Elsevier B.V. All rights reserved.