Inverted-pyramidal photonic crystal light emitting device
US7700962B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 28, 2006 |
| Grant date | Apr 20, 2010 |
| Priority date | — |
| Expiry date | Mar 30, 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 inverted pyramidal or inverted frustro-pyramidal indentations in the semiconductor material filled by a material of different refractive index and which together comprise a photonic band structure. The indentations 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 utilise the microcavity effect. A method for fabricating the device is also described which employs anisotropic wet etching to produce the inverted pyramidal or inverted frustro-pyramidal indentations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.