Semiconductor surface light emitting and receiving heterojunction device

Abstract

A surface-normal optoelectronic device is provided which includes a first semiconductor layer of a first electroconductive type, a second semiconductor layer of a second electroconductive type having a polarity inverse to that of the first electroconductive type, a semiconductor active layer, a third semiconductor layer of the first electroconductive type, and a fourth semiconductor layer of the second electroconductive type, formed on a semiconductor substrate. The second and third layers are larger in forbidden band width than the active layer, said second layer is smaller in forbidden band width than a part of the first layer contacting the second layer, and the third layer is smaller in forbidden band width than a part of the fourth layer contacting the third layer. High resistance regions are formed vertically passing through the active layer, to surround its light-emitting region and to have a resistance higher than that of that region. By providing such high resistance regions, an ineffective current to be drained out of the light emitting region can be outstandingly reduced. By setting the forbidden band widths as noted, carriers and light can be easily confined. Preferably, the first and fourth layers include layers serving as a reflecting mirror, the active layer being sandwiched by these layers. Laser emission is thereby rendered possible.