Optical properties of GaSb-based type II quantum wells as the active region of midinfrared interband cascade lasers for gas sensing applications

Photoreflectance and photoluminescence, supported by the energy level calculations in the eight-band k⋅p model including strain, have been used to study the optical properties of GaSb/AlSb/InAs/InGaSb/AlSb/GaSb type II quantum wells (QWs). The broad emission wavelength tunability in the midinfrared range has been demonstrated by the control of InAs layer thickness. The temperature dependent measurements have shown that the emission can still be efficient at room temperature in such structures, and that the temperature shift of the fundamental type II optical transition between 10 and 300 K can be significantly smaller than for type I QW systems.