Localized states emission in type-I GaAsSb/AlGaAs multiple quantum wells grown by molecular beam epitaxy

Abstract

As an important candidate for novel infrared semiconductor lasers, the optical properties of GaAsSb‐based multiple quantum wells (MQWs) are crucial. The temperature‐ and excitation power‐dependent photoluminescence (PL) spectra of the GaAs0.92Sb0.08/Al0.2Ga0.8As MQWs, which were grown by molecular beam epitaxy, were investigated and are detailed in this work. Two competitive peaks were observed from 40 K to 90 K. The peak located at the low‐energy shoulder was confirmed to be localized states emission (LE) and the high‐energy side peak was confirmed to be free‐carrier emission by its temperature‐dependent emission peak position. It is observed that the LE peak exhibited a blueshift with the increase of laser excitation power, which can be ascribed to the band filling effect of localized states. Our studies have great significance for application of GaAsSb‐based MQWs in infrared semiconductor lasers.

Lattice‐Optimized GaAsSb/InP Heterojunction Toward Both Efficient Carrier Confinement and Thermal Dissipation

“…Moreover, GaAs 1– x Sb x ( x ≈ 0.5) alloy which is lattice matched to the InP substrate is potentially important for various electronic and optoelectronic device applications due to the unique band alignment, which is more favorable for the high‐speed operation double heterojunction bipolar transistors (DHBTs) . However, the alloy fluctuations in GaAsSb always cause localized states, leading to carrier localization effects . Such localization effects have been observed in many III–V alloy compounds and dilute III–V nitrides (bismides) at low temperatures.…”

“…[5] However, the alloy fluctuations in GaAsSb always cause localized states, leading to carrier localization effects. [6,7] Such localization effects have been observed in many III-V alloy compounds [8] and dilute III-V nitrides (bismides) [9,10] at low temperatures.…”

“…[1] Because the PL was conducted at a low temperature and low excitation laser power, the PL peak is dominated by localized excitons associated with sub-bandgap potential fluctuations. [6,7] With an increase in temperature, the PL peak energy initially exhibits a redshift (T < 30 K) and then a blueshift at T < 60 K. The observed strong blueshift with increasing temperature reveals a gradual thermal activation of the localized excitons to the delocalized states. [6] Finally, at temperatures higher than %60 K, the carriers become delocalized and the PL peak energy starts to have a second redshift due to the bandgap shrinkage.…”

Optical properties of quasi-type-II structure in GaAs/GaAsSb/GaAs coaxial single quantum-well nanowires

“…As one of the most important narrow-band ternary alloys, GaAsSb is an attractive material for the fabrication of optoelectronic devices with high tunability that can cover a wide infrared wavelength range (from 870 to 1720 nm at room temperature) by adjusting the Sb content. 1 Due to the suitable energy band structure, they can form quantum wells (QWs) with other semiconductors like GaAs, 2 and AlGaAs; 3,4 this architecture would be highly suitable for optoelectronic applications such as light-emitting diodes, 5,6 lasers, 2,7 and ultrafast photodetectors. 8 When the dimension reduces, the quantum confinement effect will be more pronounced.…”

“…Before being loaded into the MBE chamber, the substrate was dealt with ultrasonic cleaning in ethanol solution for 5 min and then etched with hydrochloric acid. During the growth progress, As 4 and Sb 2 were used as the precursors. First, Ga droplets were deposited on the Si substrates with a beam equivalent pressure of Ga of 6.7 Â 10 À8 Torr.…”