| 摘要 |
<p>PURPOSE:To improve electron emission efficiency by injecting electrons from an emitter range to a base range and applying a reversed bias voltage between the base range and a collector range to emit the electrons from an electron emission surface. CONSTITUTION:In forming a heterobipolar semiconductor comprising an emitter layer 8 including a 1st band gap, a base layer 10 including a 2nd band gap which is narrower than the 1st band gap, and a collector layer 11 including an electron emission surface on an epitaxial film of GaAs provided on a substrate 1 of Si, an inclined layer 20 in which ratio of mixed crystals of a certain material is gradually changed is inserted between the emitter layer and the base layer, and electrons are injected from the emitter layer to the base layer, while a reversed bias voltage is applied between the base layer and the collector layer, so the electrons are emitted from the electron emission surface. Ratio x of A1 is gradually reduced, and x becomes 0 at the boundary with the base layer 10. Thus electron emission efficiency can be extremely improved.</p> |
