Effect of dislocation density on efficiency curves in InGaN/GaN multiple quantum well light-emitting diodes

Yoshiyuki Harada; Toshiki Hikosaka; Shigeya Kimura; Maki Sugai; Hajime Nago; Koichi Tachibana; Naoharu Sugiyama; Shinya Nunoue

doi:10.1117/12.907679

6 February 2012 Effect of dislocation density on efficiency curves in InGaN/GaN multiple quantum well light-emitting diodes

Yoshiyuki Harada, Toshiki Hikosaka, Shigeya Kimura, Maki Sugai, Hajime Nago, Koichi Tachibana, Naoharu Sugiyama, Shinya Nunoue

Author Affiliations +

Proceedings Volume 8278, Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XVI; 82780J (2012) https://doi.org/10.1117/12.907679
Event: SPIE OPTO, 2012, San Francisco, California, United States

Abstract

The contribution of reduction of threading dislocation densities (TDDs) to optical properties is investigated for InGaN/GaN light-emitting diodes (LEDs) grown on sapphire substrate. The external quantum efficiency (EQE) curves depending on the TDDs are discussed both theoretically and experimentally. At the current density of <20 A/cm², the EQE increases with decreasing the edge-type TDD from 5 e8/cm² to 2 e8/cm². The current density at the maximum EQE shifts to lower value as the edge-type TDD decreases, whereas the EQE presents no remarkable difference in the highercurrent density range irrespective of the TDD. According to the rate equation (ABC) model, the peak shift reflects the Shockley-Read-Hall non-radiative process (A coefficient). Analysis of the photoluminescence (PL) decay and the dependence of integrated PL intensity on excitation power reveals that the threading dislocations act as non-radiative recombination centers in the multiple quantum well active region. The TDD of <2 e8/cm² is required for highly efficient blue LEDs operating at current density of around 15 A/cm², whereas the TDD of <5 e8/cm² in required for the LEDs operating at around 50 A/cm².

Citation Download Citation

Yoshiyuki Harada, Toshiki Hikosaka, Shigeya Kimura, Maki Sugai, Hajime Nago, Koichi Tachibana, Naoharu Sugiyama, and Shinya Nunoue "Effect of dislocation density on efficiency curves in InGaN/GaN multiple quantum well light-emitting diodes", Proc. SPIE 8278, Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XVI, 82780J (6 February 2012); https://doi.org/10.1117/12.907679

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