High speed semiconductor device and an optelectronic device

摘要

A semiconductor device comprising a first semiconductor layer, a second semiconductor layer on the first layer, a source electrode and a drain electrode both in contact with the first layer, and a hole or electron injection electrode and a gate electrode both formed on the second layer; wherein the second semiconductor is one that has an electron affinity smaller than the first semiconductor when holes are injected or has a sum of an electron affinity and a band gap greater than the first semiconductor when electrons are injected; and wherein the injection electrode and the gate electrode are placed between the source electrode and the drain electrode in this order. In such device, the current driving capability can easily be increased by controlling the injection amount of holes or electrons and the current modulation can easily be controlled by a small capacitance gate electrode; and so operation at an extra-high frequency and an extra-high speed becomes possible.