Antonova, N.

Barabanenkov, M. Yu.

Kholopova, Yu.

Kovalchuk, A.

Polushkin, E.

Shapoval, S.

Sirotkin, V.

English

Электронная библиотека БГУ

LIGHT-EMITTING DIODE WITH TOP ELECTRODE  
AS A LAMINAR DIFFRACTION GRATING 
(приглашенный доклад) 
M.Barabanenkov(1), V.Sirotkin(1) , Yu.Kholopova(1), A. Kovalchuk(1), 
N.Antonova(2), ), E. Polushkin(1)  , S. Shapoval(1)
1 Institute of Microelectronics Technology RAS, 142432 Chernogolovka, 
Moscow region, Russia,  e-mail:  barab@iptm.ru 
2 R&D Corporation “Istok”, Fryazino, Moscow region, Russia 
 
An importance of light-emitting diodes (LEDs) as an instrumental 
ingredient in solid-state lighting is of common knowledge. The development 
of high efficiency and brightness LEDs is limited mainly due to the difficulty 
for light to escape from high refractive index semiconductors. Among a 
number of schemes considered for increasing the external quantum efficiency 
(based on the old idea of coupling the light out of the semiconductor by means 
of a high refractive index hemispherical lens), surface roughening is 
considered as one of the simpler method. However, the roughened surface 
morphology can be irregular and uncontrolled along with a significant 
problem to eliminate the strong parasitic absorption at the electrodes. We try 
to overcome the problem with electrodes. 
The device studied in the present report is a LED structure grown by 
MOCVD on a sapphire substrate. The LED structure consists of a GaN buffer 
layer, a thick n-GaN:Si layer, an InGaN/GaN active region, a p-AlGaN:Mg 
blocking layer and a p-GaN:Mg contact layer. The structure is processed in 
order to obtain circuit devices, 10 μm in diameter, including ECR-plasma 
mesa-etching, passivation by silicon nitride film, e-beam lithography and 
precision etching to produce a p-contact. Getting LED's p-contact into shape 
of laminar diffraction grating promises more efficient light output. First, 
stripe-like grooves of grating can spatially homogeneous spread of applied 
current driving across the whole structure being the grating covered structure 
surface totally. Second, the grating itself can be resonantly transparent for the 
generated light (0.45 mcm). Indeed, we describe quantitatively a resonant 
suppression of the reflection of plane monochromatic electromagnetic waves 
from the grating as a function of the grating gap (inter-rulings spacer 0.35 
mcm, rulings width 0.2 mcm), rulings thickness (0.1 mcm) and wave 
incidence angle. Mentioned optimization of p-contact allowed to increase 
LED light emission efficiency by 26% in comparison with 18% for LED with 
a conventional p-contact. 
 
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Light-emitting diode with top electrode as a laminar diffraction grating

http://elib.bsu.by/bitstream/123456789/31311/1/LIGHT-EMITTING%20DIODE%20WITH%20TOP%20ELECTRODE%20AS%20A%20LAMINAR%20DIFFRACTION%20GRATING.pdf

Light-emitting diode with top electrode as a laminar diffraction grating

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