University of California

Bell Telephone Laboratories

American Telephone & Telegraph Co., At&t Bell Laboratories

At&t Bell Laboratories

California Institute of Technology

Pierre M Petroff

Arthur C Gossard

Frédéric S Diana

James R Heath

Seung-Heon Lee

Nicholas A Melosh

Claude C A Weisbuch

Edward J Kramer

Raymond Dingle

George Arthur Rozgonyi

William Wiegmann

Robert C Miller

Antonio Badolato

James Stephen Speck

Federico Capasso

Frederic Stephane Diana

Aurelien J F David

Roger J Malik

Stephen J Pearton

Jing Shi

David D Awschalom

Herbert Kroemer

Naoto Horiguchi

James M Kikkawa

Devin Leonard

Aurélien J F David

Mohan Krishnamurthy

Hao Lee

John R Hayes

Jo Anna Johnson

Joel B Cibert

A high efficiency light emitting diode (LED) comprised of a substrate, a buffer layer grown on the substrate (if such a layer is needed), a first active region comprising primary emitting species (PES) that are electrically-injected, a second active region comprising secondary emitting species (SES) that are optically-pumped by the light emitted from the PES, and photonic crystals, wherein the photonic crystals act as diffraction gratings to provide high light extraction efficiency, to provide efficient excitation of the SES, and/or to modulate the far-field emission pattern.

Photonic structures for efficient light extraction and conversion in multi-color light emitting devices

Fabrication of metallic or non-metallic wires with nanometer widths and nanometer separation distances without the use of lithography. Wires are created in a two-step process involving forming the wires at the desired dimensions and transferring them to a planar substrate. The dimensions and separation of the wires are determined by the thicknesses of alternating layers of different materials that are in the form of a superlattice. Wires are created by evaporating the desired material onto the superlattice that has been selectively etched to provide height contrast between layers. The wires thus formed upon one set of superlattice layers are then transferred to a substrate.

Superlattice nanopatterning of wires and complex patterns

A method and resultant device, in which metal nanoparticles are self-assembled into two-dimensional lattices. A periodic hole pattern (wells) is fabricated on a photoresist substrate, the wells having an aspect ratio of less than 0.37. The nanoparticles are synthesized within inverse micelles of a polymer, preferably a block copolymer, and are self-assembled onto the photoresist nanopatterns. The nanoparticles are selectively positioned in the holes due to the capillary forces related to the pattern geometry, with a controllable number of particles per lattice point.

Fabrication method for arranging ultra-fine particles

A method for growing strain-engineered, self-assembled, semiconductor quantum dots (QDs) into ordered lattices. The nucleation and positioning of QDs into lattices is achieved using a periodic sub-surface lattice built-up on a substrate, stressor layer, and spacer layer. The unit cell dimensions, orientation and the number of QDs in the basis are tunable. Moreover, a 2D lattice can be replicated at periodic intervals along the growth direction to form a three-dimensional (3D) lattice of QDs.

Strain-engineered, self-assembled, semiconductor quantum dot lattices

A method and device for converting light from a first wavelength to a second wavelength. The method comprises the steps of exciting an electron in a quantum dot with an incident infrared photon having the first wavelength, the excited electron having a first energy, tunneling the excited electron through a barrier into a stress induced quantum dot, and recombining the excited electron with a hole in the stress induced quantum dot, therein producing a photon having the second wavelength, typically in the visible range. The device comprises a substrate, a spacer layer, coupled to the substrate, a second layer, coupled to the spacer layer, wherein the second layer comprises a different material than the spacer layer, a third layer, coupled to the second layer, wherein the third layer comprises at least one quantum dot, a fourth layer, coupled to the third layer, comprising a quantum well corresponding to each quantum dot in the third layer, a fifth layer, coupled to the fourth layer, wherein the fourth layer and fifth layer comprise a strain induced quantum dot corresponding to each quantum dot in the third layer; and a sixth layer, coupled to the fifth layer, the substrate and the sixth layer for contacting the device.

Mid infrared and near infrared light upconverter using self-assembled quantum dots

Submicron ferromagnets, of selected size and spacing, are introduced into semiconductor by means of ion implantation and subsequent heat treatments. The resulting semiconductor contains ferromagnets at high density and which exhibit Curie temperatures exceeding room temperature. The semiconductor retains its intrinsic physical properties, such as optical and transport properties, after incorporation of the ferromagnetic nanostructures.

Integrable ferromagnets for high density storage

A process for production of self-assembled quantum dots is described which does not entail any processing steps before or after growth of the quantum dots. The process uses in situ formation of three dimensional islands which occurs during epitaxy of material with a different lattice parameter than the substrate. Further deposition of the substrate material then produces single or multiple buried two dimensional layers of randomly distributed or selectively positioned and substantially uniform sized quantum dots. These layers are free of defects and interface states. The lateral dot diameters vary between 140 to 300 Angstroms by appropriate choice of deposition parameters.

Quantum dot fabrication process using strained epitaxial growth

A method for modulation doping of semiconductor heterostructures includes forming a semiconductor heterostructure comprising a substrate layer, a narrow band-gap quantum well layer, and a donor implantation layer. A focused ion beam writes across the surface of the donor implantation layer, at a maximum angle of incident less than that of the channeling half-angle .alpha. of the donor implantation layer. Channeled dopant ions penetrate deep within the donor implantation layer, far from surface damage sites, and away from the quantum well layer. The addition of a dechanneling layer within the donor implantation layer, and of a series of spacer layers, further localizes the implanted donor ions and separates these ions from the quantum well layer. Once activated by a thermal annealing process, the donor ions release carriers into the quantum well layer where carrier mobility is unimpeded by donor ion collisions. An alternative embodiment implants the donor ions before the heterostructure is completely formed. Another alternative embodiment deposits concentrations of dopant ions partially into the quantum layer, where the ions serve as point defects causing interdiffusion of the donor implantation layer material and that of the quantum well layer. Quantum well regions are formed, separated by interdiffusion regions containing donor ions.

Nanoscale modulation doping method

A method for growing a superlattice structure on a substrate. First, a periodic array of monoatomic surface steps are created on the surface of the substrate at an area to have the superlattice structure grown thereon. There is apparatus for creating a beam of a material being input thereto and for selectively including or not including respective ones of a plurality of materials within the beam. The beam is directed at the steps of the substrate. Finally, logic causes control apparatus to include and not include respective ones of the materials within the beam in a pre-established pattern of time periods which will cause the materials to be deposited on the steps in a series of stacked monolayers. Tilted Superlattices (TSLs) and Coherent Tilted Superlattices (CTSLs) are created. The method can create pseudo ternary semiconductor alloys as part of a CTSL by employing at least two binary compound semiconductor alloys in the deposition process. It can also create a quantum wire superlattice by sandwiching a thin CTSL layer between two wider band gap layers. Additionally, it can create a tilted superlattice with zero misfit strain by using three binary compounds to produce a pseudo-ternary compound in a direction parallel to the substrate normal while the tilted superlattice structure provides a desired band gap in a direction parallel to the substrate surface. One may form the CTSL as part of a field effect transistor (FET) wherein the CTSL is part of the FET gate or form the CTSL as the cladding layers of a quantum wire laser having a GaAs active layer.

Method for growing tilted superlattices

Single GaAs quantum well or single GaAs active layer or single reverse interface structures with Al.sub.x Ga.sub.1-x As barrier layers have improved qualities when one or more narrow bandgap GaAs getter-smoothing layers, which are thin, are grown and are incorporated in the barrier layer before and in close proximity to the active layer.

Semiconductor devices and methods of making such devices

A heterojunction bipolar transistor having means for changing carrier transport properties is described.

Heterojunction bipolar transistor

A method of fabricating quantum well wires and boxes is described in which interdiffusion in a semiconductor having a compositional profile is enhanced by the presence of defects created by ion implantation in localized regions.

Structures including quantum well wires and boxes

Growing community of inventors

Santa Barbara, CA, United States of America

Pierre M Petroff