TY - JOUR
T1 - Achieving uniform carrier distribution in MBE-grown compositionally graded InGaN Multiple-Quantum-Well LEDs
AU - Mishra, Pawan
AU - Janjua, Bilal
AU - Ng, Tien Khee
AU - Shen, Chao
AU - Salhi, Abdelmajid
AU - Alyamani, Ahmed Y.
AU - El-Desouki, Munir M.
AU - Ooi, Boon S.
N1 - Publisher Copyright:
© 2009-2012 IEEE.
PY - 2015/6/1
Y1 - 2015/6/1
N2 - We investigated the design and growth of compositionally graded InGaN multiple-quantum-well (MQW)-based light-emitting diodes (LEDs) without an electron-blocking layer. Numerical investigation showed uniform carrier distribution in the active region and higher radiative recombination rate for the optimized graded-MQW design, i.e., In0→ xGa1→(1-x)N/InxGa(1-x) N/Inx→0Ga(1-x)→ 1N, as compared with the conventional stepped-MQW-LED. The composition-grading schemes, such as linear, parabolic, and Fermi-function profiles, were numerically investigated for comparison. The stepped- and graded-MQW-LEDs were then grown using plasma-assisted molecular beam epitaxy through surface-stoichiometry optimization based on reflection high-energy electron diffraction in situ observations. Stepped- and graded-MQW-LED showed efficiency roll over at 160 and 275 A/cm2 $, respectively. The extended threshold current density roll-over (droop) in graded-MQW-LED is due to the improvement in carrier uniformity and radiative recombination rate, which is consistent with the numerical simulation.
AB - We investigated the design and growth of compositionally graded InGaN multiple-quantum-well (MQW)-based light-emitting diodes (LEDs) without an electron-blocking layer. Numerical investigation showed uniform carrier distribution in the active region and higher radiative recombination rate for the optimized graded-MQW design, i.e., In0→ xGa1→(1-x)N/InxGa(1-x) N/Inx→0Ga(1-x)→ 1N, as compared with the conventional stepped-MQW-LED. The composition-grading schemes, such as linear, parabolic, and Fermi-function profiles, were numerically investigated for comparison. The stepped- and graded-MQW-LEDs were then grown using plasma-assisted molecular beam epitaxy through surface-stoichiometry optimization based on reflection high-energy electron diffraction in situ observations. Stepped- and graded-MQW-LED showed efficiency roll over at 160 and 275 A/cm2 $, respectively. The extended threshold current density roll-over (droop) in graded-MQW-LED is due to the improvement in carrier uniformity and radiative recombination rate, which is consistent with the numerical simulation.
KW - Compositional grading
KW - Light emitting diodes (LEDs)
KW - polarization field
KW - semiconductor quantum well
KW - solid state lighting
KW - wavefunction overlap
UR - https://www.scopus.com/pages/publications/84930504756
U2 - 10.1109/JPHOT.2015.2430017
DO - 10.1109/JPHOT.2015.2430017
M3 - Article
AN - SCOPUS:84930504756
SN - 1943-0655
VL - 7
JO - IEEE Photonics Journal
JF - IEEE Photonics Journal
IS - 3
M1 - 7102690
ER -