On the increased efficiency in InGaN-based multiple quantum wells emitting at 530–590 nm with AlGaN interlayers

Journal Article · Wed Jan 07 00:00:00 EST 2015 · Journal of Crystal Growth

DOI:https://doi.org/10.1016/j.jcrysgro.2014.12.034· OSTI ID:1426883

Koleske, D. D. ^[1]; Fischer, A. J. ^[1]; Bryant, B. N. ^[2]; Kotula, P. G. ^[1]; Wierer, J. J. ^[1]

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1. Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
2. Univ. of New Mexico, Albuquerque, NM (United States). Center for High Technology Materials

InGaN/AlGaN/GaN-based multiple quantum wells (MQWs) with AlGaN interlayers (ILs) are investigated, specifically to examine the fundamental mechanisms behind their increased radiative efficiency at wavelengths of 530–590 nm. The Al_zGa_1-zN (z~0.38) IL is ~1–2 nm thick, and is grown after and at the same growth temperature as the ~3 nm thick InGaN quantum well (QW). This is followed by an increase in temperature for the growth of a ~10 nm thick GaN barrier layer. The insertion of the AlGaN IL within the MQW provides various benefits. First, the AlGaN IL allows for growth of the In_xGa_1-xN QW well below typical growth temperatures to achieve higher x (up to~0.25). Second, annealing the IL capped QW prior to the GaN barrier growth improves the AlGaN IL smoothness as determined by atomic force microscopy, improves the InGaN/AlGaN/GaN interface quality as determined from scanning transmission electron microscope images and x-ray diffraction, and increases the radiative efficiency by reducing non-radiative defects as determined by time-resolved photoluminescence measurements. Finally, the AlGaN IL increases the spontaneous and piezoelectric polarization induced electric fields acting on the InGaN QW, providing an additional red-shift to the emission wavelength as determined by Schrodinger-Poisson modeling and fitting to the experimental data. The relative impact of increased indium concentration and polarization fields on the radiative efficiency of MQWs with AlGaN ILs is also explored, along with implications to conventional longer wavelength emitters.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). EFRC for Solid State Lighting Science (SSLS); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE National Nuclear Security Administration (NNSA)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 1426883
• Report Number(s): SAND-2014-17728J; 537540
• Journal Information: Journal of Crystal Growth, Vol. 415, Issue C; ISSN 0022-0248
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
77 NANOSCIENCE AND NANOTECHNOLOGY
Interfaces
X-ray diffraction
Metalorganic vapor phase epitaxy
InGaN
Light-emitting diodes
Solar cells