TY - JOUR
T1 - Electroluminescence efficiency of blue InGaN/GaN quantum-well diodes with and without an n-InGaN electron reservoir layer
AU - Otsuji, N.
AU - Fujiwara, K.
AU - Sheu, J. K.
N1 - Funding Information:
The authors would like to thank H. Kostial, U. Jahn, and H. T. Grahn of Paul-Drude Institute for Solid State Electronics in Berlin, Germany for sample wiring and useful discussion. They also thank Y. Takahashi, H. Katou, and A. Satake for their experimental assistance. This work was supported in part by the Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sport, Science, and Technology of Japan under the Contract No. 16360157.
PY - 2006
Y1 - 2006
N2 - The temperature dependence of the electroluminescence (EL) spectral intensity has been investigated in detail between T=20 and 300 K at various injection current levels for a set of two blue InGaNGaN multiple-quantum-well (MQW) light-emitting diodes (LEDs) with and without an additional n -doped In0.18 Ga0.82 N electron reservoir layer (ERL). The radiative recombination efficiency of the main blue emission band (∼480 nm) is found to be significantly improved at all temperature regions and current levels when the additional ERL is introduced. For high injection currents If, i.e., large forward bias voltages Vf, a quenching of the EL intensity is observed for T<100 K for both LED structures, accompanying appearance of short-wavelength satellite emissions around 380-430 nm. Furthermore, the low-temperature intensity reduction of the main EL band is stronger for the LED without the ERL than with the ERL. For low If, i.e., small Vf, however, no quenching of the EL intensity is observed for both LEDs even below 100 K and the short-wavelength satellite emissions are significantly reduced. These results of the main blue emission and the short-wavelength satellite bands imply that the unusual evolution of the EL intensity with temperature and current is caused by variations of the actual potential field distribution due to both internal and external fields. They significantly influence the carrier capture efficiency by radiative recombination centers within the active MQW layer and the carrier escape out of the active regions into high-energy recombination centers responsible for the short-wavelength satellite emissions.
AB - The temperature dependence of the electroluminescence (EL) spectral intensity has been investigated in detail between T=20 and 300 K at various injection current levels for a set of two blue InGaNGaN multiple-quantum-well (MQW) light-emitting diodes (LEDs) with and without an additional n -doped In0.18 Ga0.82 N electron reservoir layer (ERL). The radiative recombination efficiency of the main blue emission band (∼480 nm) is found to be significantly improved at all temperature regions and current levels when the additional ERL is introduced. For high injection currents If, i.e., large forward bias voltages Vf, a quenching of the EL intensity is observed for T<100 K for both LED structures, accompanying appearance of short-wavelength satellite emissions around 380-430 nm. Furthermore, the low-temperature intensity reduction of the main EL band is stronger for the LED without the ERL than with the ERL. For low If, i.e., small Vf, however, no quenching of the EL intensity is observed for both LEDs even below 100 K and the short-wavelength satellite emissions are significantly reduced. These results of the main blue emission and the short-wavelength satellite bands imply that the unusual evolution of the EL intensity with temperature and current is caused by variations of the actual potential field distribution due to both internal and external fields. They significantly influence the carrier capture efficiency by radiative recombination centers within the active MQW layer and the carrier escape out of the active regions into high-energy recombination centers responsible for the short-wavelength satellite emissions.
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U2 - 10.1063/1.2398690
DO - 10.1063/1.2398690
M3 - Article
AN - SCOPUS:33845767529
SN - 0021-8979
VL - 100
JO - Journal of Applied Physics
JF - Journal of Applied Physics
IS - 11
M1 - 113105
ER -