Low-cadmium nanocrystalline quantum dot heterostructure
View Patent ↗A semiconductor structure has a nano-crystalline core comprising a first semiconductor material and a nano-crystalline shell comprising a second, different semiconductor material at least partially surrounding the nano-crystalline core. Either one, but not both, of the core and shell are based on cadmium-containing semiconductor materials.
1. A semiconductor structure, comprising:
a nano-crystalline core comprising a first semiconductor material; and
a nano-crystalline shell comprising a second, different semiconductor material at least partially surrounding the nano-crystalline core, wherein only the first semiconductor material is based on Cadmium (Cd) and comprises a Type II-VI material, and the second semiconductor material comprises a Type I-II-VI 2 material.
2. The semiconductor structure of claim 1 , wherein the Type II-VI material is selected from a group consisting of: CdSe or CdS.
3. The semiconductor structure of claim 1 , wherein the Type I-III-VI 2 material comprises AgGaS 2 .
4. The semiconductor structure of claim 1 , further comprising:
a nano-crystalline outer shell comprising a third, different, semiconductor material at least partially surrounding the nano-crystalline shell.
5. The semiconductor structure of claim 4 , wherein the third semiconductor material is selected from a group consisting of: ZnSe and ZnS.
6. The semiconductor structure of claim 1 , wherein the semiconductor structure comprises an amount of Cd that is substantially in compliance with a government restriction of hazardous substances.
7. The semiconductor structure of claim 1 , wherein the first semiconductor material comprises one of CdSe and CdS, and the second semiconductor material comprises AgGaS 2 .
8. The semiconductor structure of claim 7 wherein the semiconductor structure has a high PLQY with large Stokes shift, and is absorptive at wavelengths from 450 nm to 500 nm.
9. The semiconductor structure of claim 7 , wherein the nano-crystalline core and nano-crystalline shell are non-spherical in shape.
10. The semiconductor structure of claim 1 , further comprising:
an insulator coating surrounding and encapsulating the nano-crystalline core and nano-crystalline shell.
11. The semiconductor structure of claim 1 , wherein the nano-crystalline core and nano-crystalline shell form a type I hetero-structure.
12. A semiconductor structure, comprising:
a nano-crystalline core comprising a first semiconductor material; and
a nano-crystalline shell comprising a second, different semiconductor material at least partially surrounding the nano-crystalline core, wherein the first semiconductor material comprises one of CdSe and CdS, and the second semiconductor material comprises AgGaS 2 .