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Eva Repiso Menendez. Growth and hydrogenation of Sb/N materials for high efficiency mid-IR LEDs in pollutant gas detection. Personal background Bachelor in Physics Oviedo University 4 months in Italian National Laboratory TASC Project: Self-assisted n-type GaAs nanowires grown by MBE.
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Eva Repiso Menendez Growth and hydrogenation of Sb/N materials for high efficiency mid-IR LEDs in pollutant gas detection
Personal background Bachelor in Physics Oviedo University 4 months in Italian National Laboratory TASC Project: Self-assisted n-type GaAs nanowires grown by MBE M. Orru, E. Repiso et al. Adv. Funct. Mater. 26, 2836-2845 (2016)
Personal background Masters in Energies and Fuels for the future AutonomaUniveristy of Madrid 6 months part time in Crystal Growth Laboratory Project: Simulation and growth in volume of CdZnTe single crystals CrysMAS simulation of a Vertical Gradient Freeze furnace
WP 4 – Materials for environment (Eva Lancs., Mario Mont., Davide Nott.) Growth and hydrogenation of Sb/N materials for high efficiency mid-IR LEDs in pollutant gas detection Motivation for MIR LEDs gas detection CH4, CO2, CO…. - environmental pollution monitoring - optical gas sensing - chemical process control - medical diagnosis
Mid-IR LED output power • Background – Mid-IR LEDs • Main challenges • Auger, SRH non-radiative recombination • Optical extraction • Approaches • Sb nanostructures QW & QD • Dilute N LED based CO2 gas sensor GSS Ltd.
Results InAsSb/InAlAs type-I MQW Band diagram at 0 K Sample structure Electroluminescence with temperature I-V measurements of LEDs CO2 absorption
Results InAsSb/InAlAs MQW Hydrogenated 90 K Electroluminescence dependence on hydrogenation dose 300 K Electroluminescence dependence on hydrogenation dose CO2 absorption CO2 absorption
Results InAsSb/InAlAs MQW Hydrogenated 90K Electroluminescence dependence on hydrogenation dose Peak intensity Peak wavelength
Results InSb/InAs type-II QDs InSb deposition time determines QDs size InAs cap temperature influences size and intermixing InAs @470°C InSb @430°C + InAs cap InAs @430°C Mono Layers of QDs from XRD InAs InSb QDs
Summary LEDs grown containing strained InAs0.90Sb0.10 QWs Characterisation shows EL up to RT First hydrogenated mid-IR LEDs PL samples grown containing InSb QDs Shift in λ emission due to the cold cap Work in progress Effects of the cold cap on QDs morphology and defects TEM at UCA (Atif Khan) Hydrogenation at Sapienza University -Rome Band engineering InAsSb/InAlAs enables better targeting the λ Dilute N MBE
Outputs • Talks at Networks • 1st WebEx meeting (March 2016) • Growth and hydrogenation of Sb/N materials for high efficiency mid-IR LEDs in pollutant gas detection • Speaker: Eva Repiso • b) Talk at PROMIS conference (Cadiz, April 2016) • InSb QDs for high efficiency mid-IR LEDs • Speaker: Eva Repiso • Posters • a) 19th International MBE conference (Montpellier, Sept. 2016) • InSb QDs for mid-IR LEDs • Authors: E. Repiso, P. J. Carrington, A. Marshall, Q. Lu and A.Krier • Outreach • Webcast on Photonics • Day of Photonics, photos through Twitter
Future aspirations Publish high impact papers; Present talks at international conferences; Mirsens 4th (May 2017) UK semiconductors (June 2017) SPIE optics+photonics (August 2018) 20th International MBE conference (Sept 2018) Postdoc Fellowship application Academic/Industry career