Spontaneous Ridge Formation and Its Effect on Field Emission of Heavily Si-Doped AlN

From the linear relation between the anode–sample distance and the voltage, we have accurately obtained the net electric field between the anode and the sample surface. When Si is doped heavily into AlN, ridge structures with nanometer-order sharpness form spontaneously due to the facet growth. We found that the net electric field decreased with Si-dopant density (NSi). The highest field emission (FE) current density was 0.22 A/cm2. Numerical calculations show that a ridge lowers the energy barrier by about 1.5 eV, and this can explain well the ridge effect on FE.