| 摘要 |
<p>PURPOSE:To improve electron emission efficiency by injecting electrons from an emitter range toward a base range, land applying a reversed bias voltage between the base range and a collector range, so that the electrons maybe emitted from an electron emission surface. CONSTITUTION:A hetero-bipolar structure is composed of an emitter layer 2 having a 1st band gap, a base layer 6 having a 2nd band gap which is narrower than the 1st, and a collector layer 8 including an electron emission surface. Electrons are injected from the emitter layer 2 toward the base layer, while a reversed bias voltage is applied between the base layer and the collector layer, so electrons are emitted from the electron emission surface. Thus, due to structure in which band gaps are different between the emitter and the base, quantity of carriers injected is increased compared to that with uniform band gaps, and the carriers injected into the base are accelerated by the electric field, thereby kinetic energy can be improved. Thus electron emission efficiency is extremely improved.</p> |
