Gain and Threshold Current in Type II In(As)Sb Mid-Infrared Quantum Dot Lasers

Abstract

Abstract:In this work, we improved the performance of mid-infrared type II InSb/InAs quantum dot (QD) laser diodes by incorporating a lattice-matched p-InAsSbP cladding layer. The resulting devices exhibited emission around 3.1 µm and operated up to 120 K in pulsed mode, which is the highest working temperature for this type of QD laser. The modal gain was estimated to be 2.9 cm −1 per QD layer. A large blue shift (~150 nm) was observed in the spontaneous emission spectrum below threshold due to charging effects. Because of the QD size distribution, only a small fraction of QDs achieve threshold at the same injection level at 4 K. Carrier leakage from the waveguide into the cladding layers was found to be the main reason for the high threshold current at higher temperatures.

Performance characteristics of GaN/Al0.2Ga0.8N quantum dot laser at L=100Å

“…Assuming that α i = 5 cm −1 , R = 0.3, n = 1 and L c = 4.2 mm, the threshold current density J th that corresponds to the modal gain value that satisfies the oscillation condition can be obtained from the modal gain-current density plots [19,20]. Table II summarizing the results, we can deduce that the p-type doping makes it possible to increase the gain peak and to reach an emission threshold for low carrier concentrations relative to the undoped or n-doped case, which makes it possible to achieve at minimum values of threshold current densities, and that the optimum size of the cube for lowest threshold is shifted to longer length of the side because low gain can be achieved without carrier injection for the useless levels.…”

Promising features of In$_{0.5}$Ga$_{0.5}$N/Al$_{0.2}$Ga$_{0.8}$N quantum dot lasers

“…The threshold current density J th that corresponds to the modal gain value that satisfies the oscillation condition can be obtained from the modal gain-current density plots [14,15]. The variation of threshold current density on inverse cavity length for various values of indium composition (x) is shown in Figure 7, assuming that We summarize the results obtained in this work in Table 3.…”

Self-Catalyzed InSb/InAs Quantum Dot Nanowires

“…Among the various semiconductors, InSb is an attracting material for the fabrication of mid-infrared range optoelectronic devices (2–5 μm wavelength) [ 20 ], low-power high speed electronics [ 21 ], thermoelectric conversion [ 22 ], and quantum computation [ 20 , 23 ], due to its small bandgap, low effective masses, high electron mobility, and large thermo-power figure of merit [ 21 , 24 , 25 , 26 ]. InSb/InAs heterostructures represent one of the most promising material systems for optoelectronic devices operating in the mid-infrared range [ 27 ].…”

“…Moreover, InAs x Sb 1–x alloys provide the narrowest tunable bandgap for the infrared spectrum range, broadening the possible applications for devices operating in the mid and long wavelength infrared in emission or detection, especially for environmental gas detectors and security applications [ 25 , 28 , 29 , 30 ]. Since the last decade, much effort has been put into the growth of self-assembled InSb and InAsSb QDs [ 20 , 31 , 32 , 33 , 34 , 35 , 36 ]. However, the direct growth of InSb and InAsSb QDs of high crystal quality on commonly available semiconductor substrates is very challenging owing to the large lattice mismatch and to Sb segregation and surfactant effect [ 33 , 34 ].…”

“…However, the direct growth of InSb and InAsSb QDs of high crystal quality on commonly available semiconductor substrates is very challenging owing to the large lattice mismatch and to Sb segregation and surfactant effect [ 33 , 34 ]. Different approaches have been proposed for different types of substrate by introducing an intermediate layer of other materials in order to reduce the lattice mismatch [ 31 , 33 ] leading to very difficult growth protocols [ 20 , 31 , 33 ]. The NW geometry offers a great platform for improving the InAs/InSb material system quality and range of possible applications.…”