DUV LEDs based on AlGaN quantum dots

Deep ultra-violet (DUV) light emitting diodes (LED) are expected to be the next generation of UV sources, offering significant advantages such as compactness, low consumption and long lifetimes. Yet, improvements of their performances are still required and the potential of AlyGa1-yN quantum dots as DUV emitters is investigated in this study. Using a stress induced growth mode transition, quantum dots (QD) are spontaneously formed on Al0.7Ga0.3N/AlN heterostructures grown on sapphire substrates by molecular beam epitaxy. By increasing the QD Al composition, a large shift of the QD photoluminescence in the UV range is observed, going from an emission in the near UV for GaN QD down to the UVC region for Al0.4Ga0.6N QD. A similar behavior is observed for electroluminescence (EL) measurements performed on LED structures and an emission ranging from the UVA (320-340 nm) down to the UVC (265-280 nm) has been obtained. The main performances of Al0.7Ga0.3N based QD LED are presented in terms of electrical and optical characteristics. In particular, the emission dependence on the input current density, including the emitted wavelength, the optical power and the external quantum efficiency are shown and discussed.

[1]  Michael Kneissl,et al.  A Brief Review of III-Nitride UV Emitter Technologies and Their Applications , 2016 .

[2]  E. Alves,et al.  Ternary AlGaN Alloys with High Al Content and Enhanced Compositional Homogeneity Grown by Plasma-Assisted Molecular Beam Epitaxy , 2011 .

[3]  Jean-Michel Gérard,et al.  InAs quantum boxes: Highly efficient radiative traps for light emitting devices on Si , 1996 .

[4]  J. Brault,et al.  Investigation of AlyGa1−yN/Al0.5Ga0.5N quantum dot properties for the design of ultraviolet emitters , 2016 .

[5]  J. Brault,et al.  Blue-light emission from GaN∕Al0.5Ga0.5N quantum dots , 2008 .

[6]  Mathieu Leroux,et al.  Growth of GaN nanostructures with polar and semipolar orientations for the fabrication of UV LEDs , 2014, Photonics West - Optoelectronic Materials and Devices.

[7]  Nicolas Grandjean,et al.  From visible to white light emission by GaN quantum dots on Si(111) substrate , 1999 .

[8]  J. Brault,et al.  Stark effect in ensembles of polar (0001) Al0.5Ga0.5N/GaN quantum dots and comparison with semipolar (11−22) ones , 2014 .

[9]  J. Brault,et al.  Tailoring the shape of GaN/AlxGa1−xN nanostructures to extend their luminescence in the visible range , 2009 .

[10]  J. Brault,et al.  GaN/Al0.5Ga0.5N (11-22) semipolar nanostructures: A way to get high luminescence efficiency in the near ultraviolet range , 2011 .

[11]  J. Brault,et al.  Staggered vertical self-organization of stacked InAs/InAlAs quantum wires on InP(001) , 2000 .

[12]  J. Brault,et al.  Ultra-violet GaN/Al0.5Ga0.5N quantum dot based light emitting diodes , 2013 .

[13]  J. Brault,et al.  Photoluminescence properties of (Al,Ga)N nanostructures grown on Al0.5Ga0.5N (0001) , 2017 .

[14]  J. Brault,et al.  UVB LEDs Grown by Molecular Beam Epitaxy Using AlGaN Quantum Dots , 2020, Crystals.

[15]  J. Brault,et al.  Influence of the heterostructure design on the optical properties of GaN and Al0.1Ga0.9N quantum dots for ultraviolet emission , 2017 .

[16]  J. Brault,et al.  Wetting-Layer-Free AlGaN Quantum Dots for Ultraviolet Emitters , 2020 .

[17]  Joachim Piprek,et al.  How to decide between competing efficiency droop models for GaN-based light-emitting diodes , 2015 .

[18]  J. Brault,et al.  UVA and UVB light emitting diodes with AlyGa1−yN quantum dot active regions covering the 305–335 nm range , 2018, Semiconductor Science and Technology.

[19]  S. Chenot,et al.  Ge doped GaN and Al0.5Ga0.5N-based tunnel junctions on top of visible and UV light emitting diodes , 2019, Journal of Applied Physics.

[20]  J. Brault,et al.  Effects of capping on GaN quantum dots deposited on Al0.5Ga0.5N by molecular beam epitaxy , 2009 .

[21]  J. Brault,et al.  Linear alignment of GaN quantum dots on AlN grown on vicinal SiC substrates , 2003 .

[22]  Michael W. Moseley,et al.  Tunnel-injected sub-260 nm ultraviolet light emitting diodes , 2017, 1703.00117.

[23]  J. Brault,et al.  Carrier transfer and recombination dynamics of a long-lived and visible range emission from multi-stacked GaN/AlGaN quantum dots , 2010 .

[24]  J. Brault,et al.  Ultraviolet light emitting diodes using III-N quantum dots , 2016 .

[25]  J. Brault,et al.  Optical characteristics of hexagonal GaN self-assembled quantum dots: Strong influence of built-in electric field and carrier localization , 2002 .

[26]  J. Brault,et al.  Properties of AlN layers grown on c-sapphire substrate using ammonia assisted MBE , 2018, Journal of Crystal Growth.

[27]  J. Brault,et al.  AlGaN-Based Light Emitting Diodes Using Self-Assembled GaN Quantum Dots for Ultraviolet Emission , 2013 .

[28]  G. Bauer,et al.  Structural properties of self-organized semiconductor nanostructures , 2004 .

[29]  E. Monroy,et al.  Thermal stability of the deep ultraviolet emission from AlGaN/AlN Stranski-Krastanov quantum dots , 2012 .

[30]  Motoaki Iwaya,et al.  Internal Quantum Efficiency of Whole-Composition-Range AlGaN Multiquantum Wells , 2011 .

[31]  J. Brault,et al.  Internal quantum efficiencies of AlGaN quantum dots grown by molecular beam epitaxy and emitting in the UVA to UVC ranges , 2019, Journal of Applied Physics.

[32]  Yu Cao,et al.  Compositional modulation and optical emission in AlGaN epitaxial films , 2006 .

[33]  J. Brault,et al.  Polar and semipolar GaN/Al0.5Ga0.5N nanostructures for UV light emitters , 2014 .

[34]  H. Sakaki,et al.  Multidimensional quantum well laser and temperature dependence of its threshold current , 1982 .

[35]  T. Wunderer,et al.  The 2020 UV emitter roadmap , 2020, Journal of Physics D: Applied Physics.