Optical emission from Ga ionization at a field emitter

When gallium is ionized on the cap of a field emitter, the optical emission emerges from right at the cap of the emitter. This optical emission was spectroscopically studied using an optical multichannel analyzer with a resolution of 1.3 A over the range 1850–6500 A.The dominant emission is due to Ga I radiation and is likely due to the two‐body collision between atomic gallium and electrons.