Compound semiconductors
View Patent ↗Semiconductor emitting devices that offset stresses applied to a quantum well region and reduce internal fields due to spontaneous and piezoelectric polarizations are disclosed. In one embodiment, a semiconductor emitting device includes a quantum well region comprising an active layer that emits light and at least one barrier layer disposed adjacent the active layer, a means for impressing an electric field across the quantum well region to inject carriers into the quantum well region, and a means for impressing an offset electric field across the quantum well region to offset the polarization field formed in the quantum well region.
1. A semiconductor light emitting diode comprising:
a substrate;
a quantum well region disposed above a surface of the substrate, the quantum well region comprising an active layer operable to emit light and at least one barrier layer disposed adjacent to the active layer, the active layer and the barrier layer comprising II-VI semiconductors, wherein the at least one barrier layer has a composition and a crystal orientation at a selected angle relative to the substrate effective to reduce spontaneous electrical polarization in the quantum well region and effective to reduce piezoelectric fields that form in the quantum well region, the spontaneous electrical polarization and spontaneous piezoelectric fields forming an internal field across the quantum well region;
n + and p + doping regions spaced apart laterally and operable to impress an electric field across the quantum well region to inject carriers laterally into the quantum well region; and
a gate operable to impresses an offset electric field across the quantum well region perpendicularly to the plane of the quantum well region effective to substantially cancel the internal field formed in the quantum well region.
2. The semiconductor light emitting diode of claim 1 , wherein the active layer comprises CdSeS, and the barrier layer comprises MgZnS.
3. The semiconductor light emitting diode of claim 1 , wherein the active layer comprises CdSeS, and the barrier layer comprises ZnS.
4. The semiconductor light emitting diode of claim 1 , wherein the active layer comprises CdSeS, and the barrier layer comprises CdMgZnS.
5. The semiconductor light emitting diode of claim 1 , wherein the active layer comprises CdSe x S 1-x (0.6≦x≦1.0), and the barrier layer comprises MgZnS.
6. The semiconductor light emitting diode of claim 1 , wherein the active layer comprises CdSe x S 1-x (0.6≦x≦1.0), and the barrier layer comprises ZnS.
7. The semiconductor light emitting diode of claim 1 , wherein the active layer comprises CdSe x S 1-x (0.6≦x≦1.0), and the barrier layer comprises CdMgZnS.
8. A semiconductor emitting device comprising:
a substrate;
a buffer layer disposed above a surface of the substrate;
a quantum well region arranged on the buffer layer, the quantum well region comprising an active layer that emits light, the active layer disposed between a first barrier layer and a second barrier layer, the active layer and the first and second barrier layers comprising II-VI semiconductors, wherein the first and second barrier layers have a composition and a crystal orientation at a selected angle relative to the substrate effective to reduce spontaneous electrical polarization in the quantum well region and effective to reduce piezoelectric fields that form in the quantum well region, the spontaneous electrical polarization and spontaneous piezoelectric fields forming an internal field across the quantum well region;
n + and p + doping regions spaced apart laterally and operable to impress an electric field across the quantum well region to inject carriers laterally into the quantum well region; and
a gate operable to impresses an offset electric field across the quantum well region perpendicularly to the plane of the quantum well region to substantially cancel the internal field formed in the quantum well region.
9. The semiconductor emitting device of claim 8 , wherein the active layer comprises CdSeS, and both the first barrier layer and the second barrier layer comprise MgZnS.
10. The semiconductor emitting device of claim 8 , wherein the active layer comprises CdSeS, and both the first barrier layer and the second barrier layer comprise ZnS.
11. The semiconductor emitting device of claim 8 , wherein the active layer comprises CdSeS, and both the first barrier layer and the second barrier layer comprise CdMgZnS.
12. The semiconductor emitting device of claim 8 , wherein the active layer comprises CdSe x S 1-x (0.6≦x≦1.0), and both the first barrier layer and the second barrier layer comprise MgZnS.
13. The semiconductor emitting device of claim 8 , wherein the active layer comprises CdSe x S 1-x (0.6≦x≦1.0), and both the first barrier layer and the second barrier layer comprise ZnS.
14. The semiconductor emitting device of claim 8 , wherein the active layer comprises CdSe x S 1-x (0.6≦x≦1.0), and both the first barrier layer and the second barrier layer comprise CdMgZnS.