Transcript 下載/瀏覽Download

Influence of various activation temperatures on
the optical degradation of Mg doped InGaNGaN
MQW blue LEDs
C.J. Youn, T.S. Jeong, M.S. Han, J.W. Yang, K.Y. Lim, H.W. Yu
Journal of Crystal Growth
J. K. Lee
Outline






Abstract
Introduction
Experiment
Results and Discussion
Conclusion
References
Abstract
 The optical properties of the LED structure have been
investigated
by
using
the
photoluminescence
and
electroluminescence measurement.
 Both photoluminescence and electroluminescence results indicate
that near pure InN clusters exist within the InGaN layers, which
are responsible for the light emission in the LED.
 With increasing the Mg activation temperature of p-GaN layer,
the optical properties of the LED structure tended to significantly
degrade.
Experiment
P electrode
TCL
P - GaN
In0.13Ga0.87N  3nm
P-Al0.15Ga0.85N
GaN  12nm
60nm
MQW
N electrode
N – GaN
5μm
buffer
sapphire
Results and Discussion
simple
complex
Results and Discussion
 Theoretical and experimental I-V characteristics (left) and internal/external
efficiency (right) of a blue InGaN MQW LED. The die dimensions are given in the
insert. Shadowed area marks a semitransparent p-electrode, white area corresponds
to a recessed n-electrode.
Results and Discussion
 Current density distributions in the p-n junction plane computed for the LED dice
with ‘simple’ (a) and ‘complex’ (b) electrode configurations. The die area in both
cases is 1×1 mm2. The voltages applied are 7 V and 5 V for the cases (a) and (b),
respectively.
Results and Discussion
L
L
R 
A qn N D A
 I-V characteristics of the LEDs with different electrode configurations and doping in
the n-contact layer. The series resistances of the diodes are given in the respective
curves.
Conclusion
 We have suggested and validated a novel 1D/3D hybrid approach
to modelling the current spreading in III-nitride LED chips.
 The modification of the electrode configuration is found to be
much more efficient for the series resistance improvement than
the enhanced doping of the n-contact layer that plays a dominant
role in the control of the current spreading.
References
 C.J. Youn, T.S. Jeong, M.S. Han, J.W. Yang, K.Y. Lima, H.W. Yu ”
Influence of various activation temperatures on the optical
degradation of Mg doped InGaN/GaN MQW blue LEDs ”
Journal of Crystal Growth 250 (2003) 331–338.