Temperature sensitivity of mid-infrared type II “W” inter-band cascade lasers (ICL) emitting at 4.1μm at room temperature

When?

Monday 1 November 2010, 16:00

Where?

ATI Seminar Room

Open to:

Staff, Students

Speaker:

Barnabas Ikyo, PhD Student, Surrey University

Mid infrared (MIR) temperature stable continuous wave (cw) semiconductor lasers emitting in the spectral range of 3-5µm are required for applications in environmental pollution monitoring, medical diagnostics, infrared countermeasures, laser surgery and gas leakage detection. Type-I GaSb based devices have been successfully demonstrated for room temperature (RT) operation up to about 3.1µm. While quantum cascade MIR diode lasers have operated in cw mode at ambient temperatures for wavelengths above 4µm, short wavelength QCLs (<3µm) tend to suffer from inadequate band offsets and inter-valley scattering which degrade their high temperature performance [1]. InAs/GaInSb type-II “W” interband cascade lasers (ICLs) using spatially indirect transitions have yielded promising results in the desired 2.9µm to 4.2µm range, and recently operated in cw mode at ambient temperature [2]. However, they are also temperature sensitive with a T0 typically 45-50K [3] (where 1/T0 = d(lnIth)/dT ) and the cause of this is yet to be determined,  motivating the need for further study. We show that poor carrier density pinning (above threshold) with increasing temperature coupled with non radiative recombination in InAs/GaInSb “W”-lasers may contribute to the temperature sensitivity.

Barnabas A.  Ikyo1*, Igor P. Marko1, Alf. R. Adams, Stephen J. Sweeney1,
Chadwick L. Canedy2,Igor Vurgaftman2, Chul Soo Kim2, Mijin Kim2,
William W. Bewley2  and Jerry R. Meyer2
1Advanced Technology Institute and Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
2Naval Research Laboratory, Washington DC USA.