Midinfrared InGaAsSb quantum well lasers with digitally grown tensile-strained AlGaAsSb barriers

Abstract

The InGaAsSb lasers emitting in the midinfrared with strain-compensated multiple-quantum-well (MQW) active region have been grown by solid-source molecular-beam epitaxy (MBE). Digitally grown tensile-strained AlGaAsSb was employed as barriers to increase the valence-band offset for hole confinement. The laser structures were characterized by reflection high-energy electron diffraction, x-ray diffraction, and photoluminescence. The digital-growth approach for the tensile-strained AlGaAsSb barriers improved the reliability and controllability of MBE growth for the MQW active region. The optical and structural qualities of InGaAsSb MQW were improved significantly as compared to those with random-alloy barriers due to the removal of growth interruption at the barrier/well interfaces in digital growth. As a result, high-performance devices were achieved in the InGaAsSb lasers with digital AlGaAsSb barriers. A low threshold current density of 163A∕cm2 at room temperature was achieved for 1000-μm-long lasers emitting at 2.38μm. An external differential quantum efficiency as high as 61% was achieved for the 880-μm-long lasers, the highest ever reported for any lasers in this wavelength range.

Fine modulation of the energy band strategy to control the carrier confinement capability of digital alloys

“…There are numerous studies showing that DA applied in the potential barrier layer can effectively increase the quantum confinement effect on carriers [13][14][15][16]. This is beneficial to reduce the noise of optoelectronic devices and improve optoelectronic performance.…”

Numerical study on optical and electrical properties of strained GaInSb/GaInAlSb mid-infrared quantum well laser

“…In recent years the applications of Mid-infrared lasers oscillating in the wavelength range 2.0-2.5 µm are found to increase tremendously in health care, gas sensing, chemical sensing, military countermeasures, fluoride glass fiber, and infrared imaging sensors (Fard et al 2008;Li et al 2007). First mid-infrared laser was demonstrated from lead-based IV-VI semiconductors (Strauss et al 1974).…”