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Introduction

We are now on the path towards a new illumination paradigm that can radically change the way we look at light forever! This technology promises to enhance the quality, flexibility, and cost effectiveness of light delivery. Prof. Nakamura pioneered the first group-III nitride-based blue/green LEDs and group-III nitride-based violet laser diodes (LDs), bringing about a revolution in lighting technology.

LEDs are generally very long lasting and the typical red or yellow LEDs have estimated lifetimes of more than 10 years, greatly reducing energy consumption and ongoing maintenance costs. No other single lighting technology presents so much potential to conserve valuable electricity. LEDs can provide high quality lighting in an increasing number of applications and now Nakamura is moving this remarkable phenomenon in technology forwards into economic reality with a long term goal to Light-Up-The-World on implementation.

Lecture attendees will hear him talk about the ongoing innovation in solid-state lighting.

From Edison to Nakamura - meet the man who is changing history.

Register now via the links below to ensure your seat.

About the speaker

Shuji Nakamura
Materials Department and Solid State Lighting Energy Center (SSLEC),
University of California, Santa Barbara, California 93106, U.S.A.

Shuji Nakamura was born on May 22, 1954 in Ehime, Japan. He obtained B.E., M.S., and Ph.D. degrees in Electrical Engineering from the University of Tokushima, Japan in 1977, 1979, and 1994, respectively. He joined Nichia Chemical Industries Ltd in 1979. In 1988, he spent a year at the University of Florida as a visiting research associate. In 1989 he started the research of blue LEDs using group-III nitride materials. In 1993 and 1995 he developed the first group-III nitride-based blue/green LEDs. 

He also developed the first group-III nitride-based violet laser diodes (LDs) in 1995. He has received a number of awards, including: the Nishina Memorial Award (1996), MRS Medal Award (1997), IEEE Jack A. Morton Award, the British Rank Prize (1998) and Benjamin Franklin Medal Award (2002). 

He was elected as the member of the US National Academy of Engineering (NAE) in 2003. Also, he received the Millennium Technology Prize in 2006. Since 2000, he is a professor of Materials Department of University of California Santa Barbara. He holds more than 100 patents and has published more than 390 papers in this field.

About the lecture

The GaN-based blue light emitting diodes (LED) takes electrical energy and converts it to bright blue light. The light generation is very high (60%), which is much higher than a normal incandescent bulb (5%). The efficiency of white LEDs that use GaN-based blue LEDs will become higher, almost close to 100%. Then, all of the conventional lighting, such as incandescent bulbs, fluorescent lamps and others, would be replaced with the white LEDs in order to save energy and resources.

Charge separation due to spontaneous and piezoelectric polarization inherent to the wurtzite structure has deleterious effects on the performance of most c-axis oriented emitting devices. To overcome this problem, Nonpolar GaN, such as a-plain and m-plain GaN or semipolar GaN substrates have been grown. 

We reported the fabrication of violet InGaN/GaN Light Emitting Diodes (LEDs) on the first nonpolar m-plane GaN bulk substrates.1) The output power and External Quantum Efficiency (EQE) at a driving current of 20 mA were 28 mW and 45% respectively, with peak electroluminescence (EL) emission wavelength at 400 nm. The first nonpolar m-plane nitride laser diodes (LDs) were realized on low extended defect bulk m-plane GaN substrates.2) Broad area violet lasers were fabricated and tested under pulsed and CW conditions. 

These laser diodes had threshold current densities (Jth) as low as 2.3KA/cm2 for pulsed and 7.5 kA/cm2 for CW operation. Stimulated emission was observed around 400- 480nm. Also, we fabricated high-efficient violet,3) blue, green4) and yellow LEDs,5) and violet laser diodes6) on semipolar GaN bulk substrates. In order to make a real GaN bulk crystal, we have performed the ammonothermal method. Recently, we obtained the size of 6-8 mm bulk GaN crystal.7) The recent performance of Nonpolar, Semipolar and Polar (c-plain) GaN-based emitting devices, and bulk GaN growth are described.