Palo Alto Research Center Inc.

Xerox Corporation

John E Northrup

Noble Marshall Johnson

Christopher L Chua

Thomas Wunderer

Zhihong Yang

Michael A Kneissl

Thomas L Paoli

Mark Teepe

Linda T Romano

Bowen Cheng

Robert Anthony Street

Ross D Bringans

Christian G Van De Walle

Andre Strittmatter

David Kalman Biegelsen

Eric Peeters

Patrick Yasuo Maeda

William S Wong

Meng H Lean

Armin R Volkel

Jurgen Hans Daniel

Gregory Lewis Whiting

Ashish V Pattekar

Jeng Ping Lu

Michael L Chabinyc

Jaan Noolandi

Tse Nga Ng

Philip D Floyd

Gregory B Anderson

Tuan Anh Vo

Kaiser H Wong

Sanjiv Sambandan

Pengfei Qi

G A Neville Connell

Suk Choi

Dietmar P Knipp

A light emitting diode includes an active region configured to emit light, a composite electrical contact layer, and a transparent electron blocking hole transport layer (TEBHTL). The composite electrical contact layer includes tow materials. At least one of the two materials is a metal configured to reflect a portion of the emitted light. The TEBHTL is arranged between the composite electrical contact layer and the active region. The TEBHTL has a thickness that extends at least a majority of a distance between the active region and the composite electrical contact layer. The TEBHTL has a band-gap greater than a band-gap of light emitting portions of the active region. The band-gap of the TEBHTL decreases as a function of distance from the active region to the composite electrical contact layer over a majority of the thickness of the TEBHTL.

Transparent electron blocking hole transporting layer

A light emitting device includes a p-side heterostructure having a short period superlattice (SPSL) formed of alternating layers of AlGaN doped with a p-type dopant and AlGaN doped with the p-type dopant, where x&#x2264;x&#x2264;0.9. Each layer of the SPSL has a thickness of less than or equal to about six bi-layers of AlGaN.

P-side layers for short wavelength light emitters

A vertical external cavity surface emitting laser (VECSEL) structure includes a heterostructure and first and second reflectors. The heterostructure comprises an active region having one or more quantum well structures configured to emit radiation at a wavelength, &#x3bb;, in response to pumping by an electron beam. One or more layers of the heterostructure may be doped. The active region is disposed between the first reflector and the second reflector and is spaced apart from the first reflector by an external cavity. An electron beam source is configured to generate the electron beam directed toward the active region. At least one electrical contact is electrically coupled to the heterostructure and is configured to provide a current path between the heterostructure and ground.

Electron beam pumped vertical cavity surface emitting laser

Light emitting devices having an enhanced degree of polarization, P, and methods for fabricating such devices are described. A light emitting device may include a light emitting region that is configured to emit light having a central wavelength, &#x3bb;, and a degree of polarization, P, where P&#x3e;0.006&#x3bb;&#x2212;b for 200 nm&#x2264;&#x3bb;&#x2264;400 nm, wherein b&#x2264;1.5.

Ultraviolet light emitting devices having compressively strained light emitting layer for enhanced light extraction

An electronic device, including an organic semiconductor, the organic semiconductor having a first polymer having a first molecular weight and a first length, and a second polymer having a second molecular weight and a second length, wherein the second length is longer than the first length.

Organic polymer semiconductors with increased interdomain connectivity and mobility

A polarization controlled device has a first layer comprising a group III-nitride semiconductor substrate or template; a second group III-nitride semiconductor layer disposed over the group III-nitride semiconductor substrate or template; a third group III-nitride semiconductor layer disposed over the second group III-nitride semiconductor layer; and a fourth group III-nitride semiconductor layer disposed over the third group III-nitride semiconductor layer. A pn junction is formed at an interface between the third and fourth group III-nitride semiconductor layers. A polarization heterojunction is formed between the second group III-nitride semiconductor layer and the third group III-nitride semiconductor layer. The polarization junction has fixed charges of a polarity on one side of the polarization junction and fixed charges of an opposite polarity on an opposite side of the polarization junction. When unbiased, the pn junction comprises a first electric field that opposes the flow of carriers across the pn junction and the polarization junction comprises a second electric field that opposes the flow of oppositely charged carriers across the polarization junction.

Nitride semiconductor polarization controlled device

A light emitting diode includes an active region configured to emit light, a composite electrical contact layer, and a transparent electron blocking hole transport layer (TEBHTL). The composite electrical contact layer includes two materials. At least one of the two materials is a metal configured to reflect a portion of the emitted light. The TEBHTL is arranged between the composite electrical contact layer and the active region. The TEBHTL has a thickness that extends at least a majority of a distance between the active region and the composite electrical contact layer. The TEBHTL has a band-gap greater than a band-gap of light emitting portions of the active region. The band-gap of the TEBHTL decreases as a function of distance from the active region to the composite electrical contact layer over a majority of the thickness of the TEBHTL.

A light emitting device includes a p-side heterostructure having a short period superlattice (SPSL) formed of alternating layers of AlGaN doped with a p-type dopant and AlGaN doped with the p-type dopant, where x&#x2266;x&#x2266;0.9. Each layer of the SPSL has a thickness of less than or equal to about six bi-layers of AlGaN.

Light emitting devices having an enhanced degree of polarization, P, and methods for fabricating such devices are described. A light emitting device may include a light emitting region that is configured to emit light having a central wavelength, &#x3bb;, and a degree of polarization, P, where P&#x3e;0.006&#x3bb;&#x2212;b for 200 nm&#x2266;&#x3bb;&#x2266;400 nm, wherein b&#x2266;1.5.

A light emitting device includes a p-side heterostructure, an n-side heterostructure, an active region disposed between the p-side heterostructure and the n-side heterostructure. An electron blocking layer (EBL) disposed between the p-side heterostructure and the active region comprises an aluminum containing group-III-nitride alloy. An aluminum composition of the EBL decreases as a function of distance along a [0001] direction from the active region towards the p-side heterostructure over a majority of the thickness of the EBL.

Graded electron blocking layer

Optically pumped laser structures incorporate reflectors that have high reflectivity and are bandwidth limited to a relatively narrow band around the central laser radiation wavelength. In some cases, the reflectors may be &#xbe;-wavelength distributed Bragg reflectors (DBRs).

Optically pumped surface emitting lasers incorporating high reflectivity/bandwidth limited reflector

Surface emitting laser structures that include a partially reflecting element disposed in the laser optical cavity are disclosed. A vertical external cavity surface emitting laser (VECSEL) structure includes a pump source configured to emit radiation at a pump wavelength, &#x3bb;, an external out-coupling reflector, a distributed Bragg reflector (DBR,) and an active region arranged between the DBR and the out-coupling reflector. The active region is configured to emit radiation at a lasing wavelength, &#x3bb;. The VECSEL structure also includes partially reflecting element (PRE) arranged between the gain element and the external out-coupling reflector. The PRE has reflectivity of between about 30% and about 70% for the radiation at the lasing wavelength and reflectivity of between about 30% and about 70% for the radiation at the pump wavelength.

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Palo Alto, CA, United States of America

John E Northrup