A novel invention which allows the fabrication of heterojuctions consisting of relaxed layers of crystals with the same lattice structure but different lattice constants.  (more...)

A novel method to engineer optical polarization properties. (more...)

A novel method to fabricate high-performance, low voltage GaN-Based green LEDs and laser diodes (LDs).  (more...)

A novel device that uses a combination of laser diodes and phosphors to create efficient, high-power white lighting.  (more...)

A new method of relaxing buffer layers which changes the effective lattice constant of the substrate while preserving the crystal quality of above grown layers.  (more...)

A method for photoelectrochemical etching of laser facets. (more...)

A III-nitride light emitting diode (LED), in which light can be extracted from two surfaces of the LED before entering a shaped optical element and subsequently being extracted to air. (more...)

New LED structures that provide increased light extraction efficiency while retaining a planar structure. (more...)

With support from the Public Interest Energy Research (PIER) program of the California Energy Commission (CEC), the California Lighting Technology Center (CLTC) has developed the foundations for a simplified on/off and stepped dimming control system for bi-level lighting applications. The new simplified daylighting control system is composed of a microcontroller, a photo sensor, an optional occupancy sensor and optional user controls.  These components can be integrated into single product/units, or be combined through wired and/or wireless communications for a variety of products and systems.  The new technology offers auto- and continuous calibration, along with user adjustable on/off set points for light switching. California utility members of the CLTC Advisory Council (PG&E, SCE, SDGE and SMUD) have reviewed the new technology and have expressed strong interest in supporting demonstrations of emerging technologies. (more...)

A novel LED structure that shows reduced droop effects when driven with high currents. (more...)

A blue electroluminescent material based on a binaphtyl compound. (more...)

A semipolar III-nitride based laser diode employing a cavity with one or more etched facet mirrors. (more...)

An ammonothermal growth method for high-quality group III-nitride bulk crystals at commercially practical growth rates. (more...)

Multiple-light source LEDs that provide increased light extraction and conversion efficiencies, as well as increased brightness, while retaining planar structures. (more...)

A method for fabricating low cost, large scale, thin film substrates in the III-nitride materials family. (more...)

An LED design that can emit white, single, or multi-color light. (more...)

A device with increased efficiency by combining shaped high refractive index elements with an (Al, Ga, In)N LED and shaped optical elements. (more...)

A safe etching technique for use with (Al, In, Ga)N materials. (more...)

Yellow-emitting phosphors, for fabrication of white LEDs. (more...)

A novel composition for electron injection layers applicable in PLEDs. (more...)

A fuel cell is an electrochemical device similar to a battery that converts chemically bound energy directly into energy. There are various types of fuel cells and the solid oxide type fuel cell has the advantage of a high operating temperature which results in a high exhaust temperature. Researchers in UCI’s Advanced Power and Energy Program have utilized this high exhaust temperature to maximize the power efficiency and quality via recycling gas through the SOFC system. (more...)

Lighting is a major contributor to electricity consumption, accounting for 19 percent of global use and 34 percent in the U.S. The U.S. lighting market is currently dominated by the incandescent light bulb, which is only 5 percent efficient whereas the fluorescent lamp is 15 to 25 percent efficient. Solid-state luminaires, which are typically based on light-emitting diodes (LEDs), have the potential to revolutionize the industry with higher efficiency, better quality, and lower maintenance, possibly leading to a reduction of half the energy consumed by general illumination. For example, 30 percent efficiency has been achieved in a commercially available white LED and 50 percent in a laboratory white LED device. White light in such devices is produced either by combining light from different color LEDs or taking blue or near-UV light from an LED to “pump” a mixture of phosphors. The phosphor approach, when implemented with conventional phosphors, produces cold white light that is not color tunable and has non-optimal efficiency, but has the potential to overcome these shortcomings with the use of advances in materials.The appreciable energy savings derived by converting from incandescent to fluorescent lamps and solid-state lighting has spurred government measures towards phasing out incandescent light bulbs. The general lighting market is predicted to exceed $130 billion by 2011 with the LED-based share forecasted to grow to $1.4 billion by 2012. There is clearly an unmet need and great market opportunity for new energy-efficient lighting devices. (more...)

Growing public awareness of energy issues indicates a latent demand for consumer as well as industrial scale products that monitor and manage energy use and efficiency across the grid from residential and industrial buildings, to power distribution and transmission lines. This latent demand could be addressed by the latest advances in micro-electrical mechanical system (MEMS) sensors technology, wireless radios, and energy scavenging. UC Berkeley researchers have addressed this market opportunity by leveraging the technology advancements to develop improved MEMS AC electricity sensors. These Berkeley sensors are self-powered and wirelessly networked. They can be used to establish ubiquitous networks of electricity sensors thereby enabling smart grids for energy monitoring as well as management application such as demand response. (more...)

The advent of AC current proximity sensors that are passive, wireless, low-costs, and easy to install as well as maintain, enables numerous new energy management application. To take advantage of this technology-enabling opportunity, researchers at UC Berkeley have applied the latest MEMS AC sensor technology to circuit breakers. In this application, the current sensors can be easily attached to the fronts of the breakers installed in breaker boxes – these boxes are common in residential, office and commercial buildings. This type of installation doesn’t require exposure to hazardous wiring, and therefore a professional (expensive) electrician isn’t required for the installation. (more...)

Due to several inherent advantages of VCSEL devices, such as their ability to form densely packed arrays, on-wafer testing, and low power consumption, VCSELs offer a lower cost alternative to traditional edge-emitting lasers and improved performance over light emitting diodes (LEDs). Until the development of the present invention, (Ga,In,Al)N VCSELs only existed as optically pumped structures. Such structures require the implementation of large and costly pumping lasers, which limits their practical and commercial utility. (more...)

Triplet emitters are promising materials for creating bright organic light emitting diodes (OLEDs). Iridium (Ir) organometallic complexes are especially attractive because of their high quantum yield of phosphorescence and their tunability over a broad emissive spectral range. However, at high carrier injection rates, saturation of emissive states and triplet-triplet quenching limits OLED performance. Thus, there is a need to accelerate Ir radiative decay in OLEDs while keeping other optical properties unperturbed. (more...)

Due to the lack of availability of crystalline GaN substrates, epitaxy of GaN is most commonly performed on sapphire or silicon carbide substrates. GaN of comparable quality has been achieved on both types of substrates using a two step growth process. The process involves depositing a thin AIN or GaN layer at temperatures between 400 and 900 C, ensuring a complete wetting of the sapphire or SiC substrate, followed by the deposition of the main layer at temperatures above 1000 C. Depending on the actual growth condition, GaN layers with dislocation densities between 108 to 109 cm-2 can be obtained.  A process known as lateral epitaxial overgrowth (LEO) was developed to improve the structural properties of such GaN layers. In this method, the GaN layer is partially covered with a mask. Growth starts exclusively in the remaining openings and the layer laterally overgrows the mask regions. Almost dislocation free material is obtained above the masked regions but dislocations remain above the open areas and at the intersections of merging growth fronts. The procedure can be repeated to deal with the remaining dislocations by placing the mask on the former openings and intersections. The resulting GaN epitaxial layers are of high quality, but the fabrication process involves several alternating growth and processing steps and very thick GaN films are deposited. These problems make the LEO approach very expensive and may limit its application to devices whose properties are extremely sensitive with respect to the presence of dislocations. (more...)