Application of semiconductor quantum dot phosphors in nanopillar light emitting diodes
AssigneeThe Penn State Research Foundation
InventorsFan Zhang, Jian Xu, Suzanne Mohney
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Abstract
A quantum well-based p-i-n light emitting diode is provided that includes nanopillars with an average linear dimension of between 50 nanometers and 1 micron. The nanopillars include a laminar layer of quantum wells capable of non-radiative energy transfer to quantum dot nanocrystals. Quantum dot-Quantum well coupling through the side walls of the nanopillar-configured LED structure achieves a close proximity between quantum wells and quantum dots while retaining the overlying contact electrode structures. A white LED with attractive properties relative to conventional incandescent and fluorescence lighting devices is produced.
Claims21
A quantum well-based p-i-n light emitting diode comprising:
- a substrate;
- a first ohmic contact layer directly or indirectly layered on said substrate;
- a first electrode in electrical communication with said first ohmic contact;
- an n-type or p-type layer on said ohmic contact layer;
- a plurality of nanopillars that have a mean nanopillar average linear dimension of between 50 nanometers and 1 micron and each of said plurality of nanopillars having a height, each of said plurality of nanopillars defined by a sidewall, at least one laminar semiconductor quantum well having a quantum well band gap existing along the height intermediate between an said n-type or p-type layer and an oppositely doped layer to said n-type or p-type layer;
- a plurality of quantum dot semiconductor nanoparticles contacting the sidewall proximal to the at least one laminar semiconductor quantum well, said plurality of quantum dot semiconductor nanoparticles having band gaps that are less than or equal to the quantum well bandgap;
- a second ohmic contact layer directly or indirectly in electrical contact with said oppositely doped layer;
- and
- a second electrode in electrical communication with said second ohmic contact and forming an electrical circuit with said first electrode.
A light emitting diode comprising:
- a substrate;
- a first ohmic contact layer of n+ GaN directly or indirectly layered on said substrate;
- a first n-type electrode in electrical communication with said first ohmic contact;
- an n-type n-doped GaN layer on said ohmic contact layer;
- a plurality of nanopillars that have a mean nanopillar average linear dimension of between 50 nanometers and 1 micron and each of said plurality of nanopillars having a height, each of said plurality of nanopillars defined by a sidewall, at least one InGaN quantum well existing along the height intermediate between an said n-type n-doped GaN layer and a p-type p-doped GaN doped layer;
- a plurality of quantum dot semiconductor nanoparticles contacting the sidewall proximal to the InGaN quantum well, said plurality of quantum dot semiconductor nanoparticles having band gaps that are less than a band gap for the at least one InGaN quantum;
- a second ohmic contact layer of p+ GaN directly or indirectly in electrical contact with said p-type p-doped GaN doped layer;
- and
- a second electrode in electrical communication with said second ohmic contact and forming an electrical circuit with said first electrode.
Dependencies are inferred from the claim text.