Pyramidal photonic crystal light emitting device
US7615398B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 28, 2006 |
| Grant date | Nov 10, 2009 |
| Priority date | — |
| Expiry date | Mar 19, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10H20/872
Abstract
A light-emitting device (LED) is described which exhibits high extraction efficiency and an emission profile which is substantially more directional than from a Lambertian source. The device comprises a light generating layer disposed between first and second layers of semiconductor material, each having a different type of doping. An upper surface of the first layer has a tiling arrangement of pyramidal or frustro-pyramidal protrusions of semiconductor material surrounded by a material of different refractive index which together comprise a photonic band structure. The protrusions and their tiling arrangement are configured for efficient extraction of light from the device via the upper surface of the first layer and in a beam that is substantially more directional than from a Lambertian source An enhanced device employs a reflector beneath the second layer to utilize the microcavity effect. A method for fabricating the device is also described which employs anisotropic wet etching to produce the pyramidal or frustro-pyramidal protrusions
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.