Quantum well device
An apparatus includes a primary planar quantum well and a planar distribution of dopant atoms. The primary planar quantum well is formed by a lower barrier layer, a central well layer on the lower barrier layer, and an upper barrier layer on the central well layer. Each of the layers is a semiconductor layer. One of the barrier layers has a secondary planar quantum well and is located between the planar distribution of dopant atoms and the central well layer. The primary planar quantum well may be undoped or substantially undoped, e.g., intrinsic semiconductor.
1. A method, comprising:
forming a primary planar quantum well by growing a semiconductor lower barrier layer over a crystalline substrate, growing a semiconductor central well layer on the lower barrier layer, and growing a semiconductor upper barrier layer on the central well layer; and
forming a planar distribution of dopant atoms above the substrate; and
wherein the growing of one of the barrier layers includes forming a secondary planar quantum well therein;
wherein the planar distribution of dopant atoms is located above or below the primary planar quantum well;
wherein the secondary planar quantum well is formed of a bottom barrier layer, a second well layer on the bottom barrier layer, and a top barrier layer on the second well layer; and
wherein the second well layer is at least five times narrower than the central well layer of the primary planar quantum well.
2. The method of claim 1 , wherein the primary planar quantum well is formed of undoped semiconductor.
3. The method of claim 1 , wherein the growing of another of the barrier layers includes forming a secondary planar quantum well in the another of the barrier layers.
4. The method of claim 1 , wherein the one of the barrier layers includes a plurality of secondary planar quantum wells therein.
5. The method of claim 1 , further comprising:
forming another planar distribution of dopant atoms above the substrate such that one of the planar distributions is located on each side of the primary planar quantum well.
6. The method of claim 1 , wherein the central well layer and the barrier layers are formed of alloys of Group III-V semiconductors.
7. A method, comprises:
applying crossed electric and magnetic fields across a planar quantum well multilayer structure to cause a current to flow in the multilayer structure; and
wherein the structure includes a primary quantum well and a planar distribution of dopant atoms;
wherein the primary quantum well is formed by semiconductor lower barrier layer, a semiconductor central well layer on the lower barrier layer, and a semiconductor upper barrier layer on the central well layer;
wherein each barrier layer has a secondary planar quantum well therein and one of the barrier layers is located between the planar distribution of dopant atoms and the central well layer;
wherein the secondary planar quantum well is formed of a bottom barrier layer, a second well layer on the bottom barrier layer, and a top barrier layer on the second well layer; and
wherein the second well layer is at least five times narrower than the central well layer of the primary planar quantum well.