Interface Intermixing in Type II InAs/GaInAsSb Quantum Wells Designed for Active Regions of Mid-Infrared-Emitting Interband Cascade Lasers

Abstract

The effect of interface intermixing in W-design GaSb/AlSb/InAs/Ga 0.665 In 0.335 As x Sb 1 − x /InAs/AlSb/GaSb quantum wells (QWs) has been investigated by means of optical spectroscopy supported by structural data and by band structure calculations. The fundamental optical transition has been detected at room temperature through photoluminescence and photoreflectance measurements and appeared to be blueshifted with increasing As content of the GaInAsSb layer, in contrast to the energy-gap-driven shifts calculated for an ideally rectangular QW profile. The arsenic incorporation into the hole-confining layer affects the material and optical structure also altering the InAs/GaInAsSb interfaces and their degree of intermixing. Based on the analysis of cross-sectional transmission electron microscopy images and energy-dispersive X-ray spectroscopy, we could deduce the composition distribution across the QW layers and hence simulate more realistic confinement potential profiles. For such smoothed interfaces that indicate As-enhanced intermixing, the energy level calculations have been able to reproduce the experimentally obtained trend.

Ultrafast infrared spectroscopy of InAs/GaSb and InAs/InAsSb type-II superlattices

“…1, which resulted in the energy of 275meVthat being too high to match the transitions as seen in the samples. A natural occurrence regarding the interface in semiconductor nanostructures is the diffusion of the nearby atoms 36 , which effectively changes the shape of the potential well. To match the energy from the experiment, 1.3nm of the structure near the interface was converted into Ga(x)In(1-x)As(y)Sb(1-y) alloy allowing for a smooth transition from pure InAs to pure GaSb.…”

Carrier dynamics of type-II InAsSb/GaAsSb W-quantum wells emitting in mid-infrared

“…The energy shift could be connected to the effect of interface intermixing inside a quantum well. 8,16 From the growth point of view, the more soaking time is introduced, the less diffused the interface in the sample is. This phenomenon is explained by difference in the wavefunctions inside the quantum wells caused by not ideally rectangular shape of the interface.…”

Optical spectroscopy studies of atom intermixing in the core versus growth temperature of the claddings in MOCVD-grown quantum cascade lasers

“…More details can be found in ref. [28][29][30]. In our case we reduced problem of hundreds of layers to those connected with section responsible for emission (main four QWs).…”