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Abstract: Vertical-cavity surface-emitting lasers are attractive light sources particularly for gas-sensing applications. Using the AlGaInAs/InP material system, an emission wavelength ranges from 1.3 to 2.05μm has already been achieved [G. Boehm, M. Ortsiefer R. Shau, J. Rosskopf, C. Lauer, M. Maute, F. Köhler, F. Mederer, R. Meyer, M.-C. Amann, in: Proceedings of MBE XII, J. Crystal Growth (2002) pp. 748–753]. Within this range, absorption lines of gases like H2S (1590nm), CH4 (1654nm), H2O (1877nm) and CO2 (2004nm) are detectable [G. Totschnig, M. Lackner, R. Shau, M. Ortsiefer, J. Rosskopf, M.-C. Amann, F. Winter, Meas. Sci. Technol. 14 (2003) 472]. The aim of this work is a further expansion of the emission wavelength up to 2.3μm, exploiting the well-known InP-based material system and the fabrication technique of buried tunnel junction (BTJ) VCSELs [R. Shau, M. Ortsiefer, J. Rosskopf, G. Boehm, C. Lauer, M. Maute, M.-C. Amann, in: Proceedings of SPIE, 5364 (2004) 1–15] to reach the technologically important absorption lines of carbon monoxide (CO) around 2.33μm. [Copyright &y& Elsevier]

In this Letter, the thermal stability of GaInAsSb grown by molecular-beam epitaxy was investigated. We found a strong blueshift for both bulk material and multiple-quantum-well (MQW) structures caused by thermal annealing. The shift is almost independent of design parameters such as indium concentration, strain, and growth parameters such as temperature. For a 500-nm-thick GaInAsSb bulk layer, a blueshift of 83 meV was found after annealing for 2 h at 520 °C, whereas for MQW structures the maximum shift was 61 meV. [ABSTRACT FROM AUTHOR]

A tunnel junction for intradevice contacts on GaSb substrates has been realized. By using solid source molecular beam epitaxy, we have fabricated abrupt, heavily doped homo- and heterojunctions of InAssSbd and GaSb to form a low resistive ohmic tunnel junction. The resitivity achieved was as low as 2.6310-5 Ω cm2. [ABSTRACT FROM AUTHOR]