TY - JOUR
T1 - Achieving Uniform Carriers 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
AU - El-Desouki, Munir
AU - Ooi, Boon S.
N1 - KAUST Repository Item: Exported on 2020-10-01
PY - 2015/5/6
Y1 - 2015/5/6
N2 - We investigated the design and growth of compositionally-graded InGaN multiple quantum wells (MQW) based light-emitting diode (LED) without an electron-blocking layer (EBL). 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 to 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-LED were then grown using plasma assisted molecular beam epitaxy (PAMBE) through surface-stoichiometry optimization based on reflection high-energy electron-diffraction (RHEED) in-situ observations. Stepped- and graded-MQW-LED showed efficiency roll over at 160 A/cm2 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, consistent with the numerical simulation.
AB - We investigated the design and growth of compositionally-graded InGaN multiple quantum wells (MQW) based light-emitting diode (LED) without an electron-blocking layer (EBL). 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 to 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-LED were then grown using plasma assisted molecular beam epitaxy (PAMBE) through surface-stoichiometry optimization based on reflection high-energy electron-diffraction (RHEED) in-situ observations. Stepped- and graded-MQW-LED showed efficiency roll over at 160 A/cm2 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, consistent with the numerical simulation.
UR - http://hdl.handle.net/10754/552801
UR - http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=7102690
UR - http://www.scopus.com/inward/record.url?scp=84930504756&partnerID=8YFLogxK
U2 - 10.1109/JPHOT.2015.2430017
DO - 10.1109/JPHOT.2015.2430017
M3 - Article
SN - 1943-0655
VL - 7
SP - 1
EP - 9
JO - IEEE Photonics Journal
JF - IEEE Photonics Journal
IS - 3
ER -