Heterojunction step doped barrier cathode emitter

摘要

This invention discloses an emitter for a vacuum microelectronic device. The emitter includes a heterojunction step-doped barrier comprised of a first gallium arsenide region, an aluminum gallium arsenide region adjacent the first gallium arsenide region, and a second gallium arsenide region adjacent the aluminum gallium region and opposite to the first gallium arsenide region. The first gallium arsenide region includes a layer of heavily doped n-type gallium arsenide. The aluminum gallium arsenide region includes an intrinsic layer and a heavily doped p-type layer. The second gallium arsenide region includes a heavily doped p-type layer adjacent the aluminum gallium arsenide region, an intrinsic layer and a heavily doped n-type layer adjacent a vacuum region. In addition, a graded layer between the first gallium arsenide layer region and the aluminum gallium arsenide region is provided. Ohmic contacts are fabricated on the outer surfaces of the first gallium arsenide layer and the second gallium arsenide layer. An appropriate potential is applied across the ohmic contacts such that most of the electrons from the first gallium arsenide region have enough kinetic energy to transcend the vacuum barrier potential and be emitted into the vacuum region.