Simplified electro-optical model for device and circuit simulations of light-emitting diodes (LEDs)

Abasifreke U Ebong; Evan Downey; Stephen Arthur; Xiana C. Cao; Stephen LeBoeuf; Danielle W Merfeld

doi:10.1117/12.511885

26 January 2004 Simplified electro-optical model for device and circuit simulations of light-emitting diodes (LEDs)

Abasifreke U Ebong, Evan Downey, Stephen Arthur, Xiana C. Cao, Stephen LeBoeuf, Danielle W Merfeld

Proceedings Volume 5187, Third International Conference on Solid State Lighting; (2004) https://doi.org/10.1117/12.511885
Event: Optical Science and Technology, SPIE's 48th Annual Meeting, 2003, San Diego, California, United States

Abstract

In this paper we present the electro-optical model, using Aimspice in conjunction with a resistor network, for evaluating the LED designs for optimum uniform current spreading and efficient light extraction. Since high brightness is a critical factor for solid-state lighting, the ability for LED designs to be scalable is important, and we use the pinwheel design, which is aimed at increasing the p-contact area to aid in uniform current spreading, to demonstrate our model. The pinwheel LED design does not scale up because the percentage current uniformity decreases with device size and bias current. To validate the model the current voltage characteristics curves for the two LED sizes (X and 3X) are matched and the recombination saturation current densities values extracted as 7.8 x 10^-8 A/cm² and 8.6 x 10^-9 A/cm², respectively. The tunneling saturation current densities for smallest LED, X, is two orders of magnitude lower than the larger device (3X). Although the larger the LED the higher the photon generation, only a small fraction of these photons can escape the device. The largest photon density is generated under the p-metal contact, with decreasing generation towards the edge of the mesa. Since the metal is opaque to the photons, there is that tendency for most of the photons in this region to bounce back and forth in the device and finally get absorbed. For the 3X pinwheel LED at 20 mA forward current, the complimentary experimental and calculated results show that only 2.2% of the generated photons can escape the active region and make it to the outside world.

Citation Download Citation

Abasifreke U Ebong, Evan Downey, Stephen Arthur, Xiana C. Cao, Stephen LeBoeuf, and Danielle W Merfeld "Simplified electro-optical model for device and circuit simulations of light-emitting diodes (LEDs)", Proc. SPIE 5187, Third International Conference on Solid State Lighting, (26 January 2004); https://doi.org/10.1117/12.511885

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KEYWORDS

Light emitting diodes

Electro optical modeling

Electro optics

Instrument modeling

Device simulation

Data modeling

Metals

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