Electron emission from a GaN planar-doped-barrier hot-electron emitter with piezoelectric surface barrier lowering (i.e., no cesiation) was reported. The piezoelectric effect in the InGaN, which is produced by the strain from the pseudomorphic growth of InGaN on top of GaN, was utilized to lower the surface barrier, replacing the cesiation. used before which is the major reason for the degradation. The potential drop produced by the piezoelectric field can lower the effective electron affinity. The structure of the planar electron emitter consisted of an In0.1Ga0.9N cap layer to lower the surface barrier, a i-p-i layer to form the planar-doped-barrier, and n + GaN buffer to provide electrons. The sample was grown by molecular beam epitaxy and was fabricated to a diode-based planar emitter with an air-bridge anode. The emission current about 5 X 10(-5) A/cm(2) was measured with efficiency of 5.7 X 10(-7). The low current and efficiency are due to the oxidation of the surface, dislocation-assisted tunneling current, and low breakdown. (C) 2003 American Vacuum Society.