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Dive into the research topics where Rafael I. Aldaz is active.

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Featured researches published by Rafael I. Aldaz.


Applied Physics Letters | 2012

Bulk GaN based violet light-emitting diodes with high efficiency at very high current density

Michael Joseph Cich; Rafael I. Aldaz; Arpan Chakraborty; Aurelien J. F. David; Michael J. Grundmann; Anurag Tyagi; Meng Zhang; Frank M. Steranka; Michael R. Krames

We present experimental results on III–nitride light-emitting diodes emitting at 410 nm, grown on low-defectivity bulk GaN substrates. The epitaxial layers are optimized for high peak efficiency and maintain efficiency at very high current densities. We use a volumetric device architecture with surface roughness to maximize light extraction efficiency. We report an external quantum efficiency of 68% at 180 A cm−2. No current crowding is observed at high current density. We also demonstrate flat-line reliable operation to over 1000 h.


Applied Physics Letters | 2015

Bulk GaN flip-chip violet light-emitting diodes with optimized efficiency for high-power operation

Christophe A. Hurni; Aurelien J. F. David; Michael Joseph Cich; Rafael I. Aldaz; Bryan Ellis; Kevin Huang; Anurag Tyagi; Remi Delille; M. D. Craven; Frank M. Steranka; Michael R. Krames

We report on violet-emitting III-nitride light-emitting diodes (LEDs) grown on bulk GaN substrates employing a flip-chip architecture. Device performance is optimized for operation at high current density and high temperature, by specific design consideration for the epitaxial layers, extraction efficiency, and electrical injection. The power conversion efficiency reaches a peak value of 84% at 85 °C and remains high at high current density, owing to low current-induced droop and low series resistance.


Applied Physics Letters | 2014

High light extraction efficiency in bulk-GaN based volumetric violet light-emitting diodes

Aurelien J. F. David; Christophe A. Hurni; Rafael I. Aldaz; Michael Joseph Cich; Bryan Ellis; Kevin Huang; Frank M. Steranka; Michael R. Krames

We report on the light extraction efficiency of III-Nitride violet light-emitting diodes with a volumetric flip-chip architecture. We introduce an accurate optical model to account for light extraction. We fabricate a series of devices with varying optical configurations and fit their measured performance with our model. We show the importance of second-order optical effects like photon recycling and residual surface roughness to account for data. We conclude that our devices reach an extraction efficiency of 89%.


Archive | 2012

Led with remote phosphor layer and reflective submount

Aurélien David; Rafael I. Aldaz; Mark Butterworth; Serge J. Bierhuizen


Archive | 2012

Contact for a semiconductor light emitting device

Rafael I. Aldaz; John E. Epler; Patrick N. Grillot; Michael R. Krames


Archive | 2009

Silicone based reflective underfill and thermal coupler

Rafael I. Aldaz; Grigoriy Basin; Paul S. Martin; Michael R. Krames


Archive | 2013

DENSE-LUMINESCENT-MATERIALS-COATED VIOLET LEDS

Frank M. Steranka; Rafael I. Aldaz; Seshasayee Ankireddi; Troy A. Trottier; Rohit Modi; Rajarshi Saha


Archive | 2012

Light emitting device with trenches and a top contact

Rafael I. Aldaz; Aurélien David


Archive | 2010

Method of forming a dielectric layer on a semiconductor light emitting device

Rafael I. Aldaz; James G. Neff


Archive | 2011

Method and system for dicing substrates containing gallium and nitrogen material

Michael R. Krames; Tai Margalith; Rafael I. Aldaz

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Troy A. Trottier

Philips Lumileds Lighting Company

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Aurélien David

Philips Lumileds Lighting Company

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Grigoriy Basin

Philips Lumileds Lighting Company

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Kevin Huang

University of South Carolina

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