X-ray induced modification of electronic properties of boron nitride thin films

X-ray induced modification of the electronic properties of nanocrystalline boron nitride (BN) films with different compositions and carbon impurity co ntents is reported. The related changes of the surface composition and vale nce band structures of the irradiated films are discussed. X-ray irradiatio n of nanocrystalline BN films is shown to widen areas with intermediate val ues of electroconductivity (associated with areas of high emission density) and to increase the average value of electroconductivity by redistributing surface potentials and electron emission sites. Improvement of the field e mission is observed with both increasing electron current and diminishing t hresholds. Longer x-ray irradiation times yield greater improvement. (C) 20 00 American Institute of Physics. [S0021- 8979(00)03621-5].