Journal of Physical Chemistry & Biophysics
Open Access
ISSN: 2161-0398
ISSN: 2161-0398
A Krier
Lancaster University, UK
Keynote: J Phys Chem Biophys
The mid-infrared spectral range is technologically important for a variety of applications including gas sensing, optical spectroscopy, bio-medical diagnostics etc. Although InSb QDs have shown electroluminescence up to room temperature and are a promising candidate for diode lasers at wavelengths longer than 3 �?¼m, there have been only a few reports of InSb QD lasers. In this work, we demonstrate coherent emission from InSb QDs at wavelengths between 3.02 �?¼m and 3.11 �?¼m at temperature, Tmax up to 120 K using pulsed excitation, with a threshold current density, Jth~1.6 kA cm-2 at 4 K. The gain and spectral tuning behaviour were also investigated.We developed a hybrid laser structure containing ten sheets of sub-monolayer InSb QDs in an InAs waveguide sandwiched between a p-InAs0.61Sb0.13P0.26 lower cladding layer grown by liquid phase epitaxy and an n+ -InAs plasmonic upper cladding layer grown by MBE. The laser peak blue shifts with increasing temperature when T<50 K. For T>50 K, the peak moves to longer wavelength as temperature increases. The modal gain of the laser was extracted from lasers with different cavity lengths resulting in a value of 29 cm-1, (or 2.9 cm-1 per InSb QD layer), which is close to that found in type II QW lasers emitting at similar wavelengths. The material gain was estimated to be 19 x104 cm-1, which is similar to that for type I QDs.
A Krier is professor of physics at Lancaster University where he is director of the Quantum Technology Centre. He obtained his PhD in 1983 and joined Lancaster in 1989, where he founded the mid-infrared optoelectronics research group. He was promoted to Reader in 1999, then to Professor in 2003 and has published more than 190 papers. He has worked extensively on mid-infrared (2-5 μm)materials and devices and in 1996 he founded the international mid-infrared materials & devices conference (MIOMD). His recent work concerns antimonide nanostructures and dilute nitride alloys for use in mid-infrared lasers, photodetectors and solar cells.
Email: a.krier@lancaster.ac.uk