Ultrafast carrier relaxation in group-III nitride multiple quantum wells

Umit Ozgur; Henry O. Everitt; Stacia Keller; Steven P. DenBaars; Lei He; Hadis Morkoc

doi:10.1117/12.529426

16 June 2004 Ultrafast carrier relaxation in group-III nitride multiple quantum wells

Umit Ozgur, Henry O. Everitt, Stacia Keller, Steven P. DenBaars, Lei He, Hadis Morkoc

Proceedings Volume 5352, Ultrafast Phenomena in Semiconductors and Nanostructure Materials VIII; (2004) https://doi.org/10.1117/12.529426
Event: Integrated Optoelectronic Devices 2004, 2004, San Jose, CA, United States

Abstract

In this study, stimulated emission (SE) and ultrafast carrier relaxation are explored in InGaN and AlGaN/GaN multiple quantum wells (MQWs). The SE threshold densities (I_th) in InGaN MQWs increase with increasing QW depth. By contrast, no significant variation is observed in AlGaN/GaN MQWs with varying barrier height and growth conditions (Ga-rich and N-rich). Wavelength non-degenerate time-resolved differential transmission (TRDT) measurements reveal that increased non-radiative recombination and fast capture of carriers to the localized states below the SE energy in deeper InGaN MQWs are responsible for the increased I_th. At high excitation densities SE is shown to remove carriers efficiently from the QWs with a time constant of a few picoseconds, causing carriers at higher energies to cascade down and refill these SE-emptied states. The strength and decay times of the SE feature, which are resolved from the spectrally integrated TRDT data, are seen to vary as a function of excitation energy and density. The fast, SE-accelerated decay in AlGaN MQWs occurs more than twice as fast as in InGaN MQWs for similar excitation densities. More importantly, recombination times are an order of magnitude faster in AlGaN MQWs than in InGaN MQWs.

Citation Download Citation

Umit Ozgur, Henry O. Everitt, Stacia Keller, Steven P. DenBaars, Lei He, and Hadis Morkoc "Ultrafast carrier relaxation in group-III nitride multiple quantum wells", Proc. SPIE 5352, Ultrafast Phenomena in Semiconductors and Nanostructure Materials VIII, (16 June 2004); https://doi.org/10.1117/12.529426

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available