InGaN/GaN field emitters with a piezoelectrically-lowered surface barrier

The operating characteristics of field emitters are exponentially dependent on two device parameters: the field enhancement factor and the surface energy barrier height. In addition to these device parameters, the practical use of field emitters as electron sources is dependent on the stability and uniformity of field emission. We have investigated field emission from GaN field emitters because GaN has a high resistance to sputtering and is chemically inert. One drawback of GaN field emitters is that they are not easily sharpened. Thus, to lower the operating voltage of GaN-based field emitters we have investigated the lowering of the surface energy barrier using a strained-layer of InGaN on GaN field. The piezoelectric polarization produced in the strained InGaN forms a dipole much like the dipole formed by coating a surface with an electropositive adsorbate.