Theory of InGaBiAs dilute bismide alloys for highly efficient InP-based mid-infrared semiconductor lasers

Semicond. Sci. Technol.

Xiong

Sweeney

et al. 2018

We present a theoretical analysis and optimisation of the properties and performance of midinfrared semiconductor lasers based on the dilute bismide alloy InxGa1−xAs1−yBiy, grown on conventional (001) InP substrates. The ability to independently vary the epitaxial strain and emission wavelength in this quaternary alloy provides significant scope for band structure engineering. Our calculations demonstrate that structures based on compressively strained InxGa1−xAs1−yBiy quantum wells (QWs) can readily achieve emission wavelengths in the 3 -5 µm range, and that these QWs have large type-I band offsets. As such, these structures have the potential to overcome a number of limitations commonly associated with this application-rich but technologically challenging wavelength range. By considering structures having (i) fixed QW thickness and variable strain, and (ii) fixed strain and variable QW thickness, we quantify key trends in the properties and performance as functions of the alloy composition, structural properties, and emission wavelength, and on this basis identify routes towards the realisation of optimised devices for practical applications. Our analysis suggests that simple laser structures -incorporating InxGa1−xAs1−yBiy QWs and unstrained ternary In0.53Ga0.47As barriers -which are compatible with established epitaxial growth, provide a route to realising InP-based mid-infrared diode lasers.

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Theory and design of In_xGa_1−xAs_1−yBi_ymid-infrared semiconductor lasers: type-I quantum wells for emission beyond 3μm on InP substrates

Semicond. Sci. Technol.

Xiong

Sweeney

et al. 2018

“…Turning our attention to Auger recombination, we recall that for (In)GaAs 1− x Bi x alloys and type-I QWs grown on GaAs and InP substrates it has been proposed to use Bi incorporation to obtain a band structure in which Δ SO > E g , thereby exploiting conservation of energy to eliminate the dominant Auger recombination process involving the spin-split-off VB 15 16 17 61 62 . Due to the aforementioned reduction in the Bi and N compositions required to obtain long-wavelength emission in GaAs 1− x Bi x /GaN y As 1− y type-II QWs, a band structure having Δ SO > E g is not generally present.…”

Section: Routes To Optimised Devicesmentioning

confidence: 99%

GaAs1−xBix/GaNyAs1−y type-II quantum wells: novel strain-balanced heterostructures for GaAs-based near- and mid-infrared photonics

Jin

Marko

et al. 2017

Sci Rep

Self Cite

The potential to extend the emission wavelength of photonic devices further into the near- and mid-infrared via pseudomorphic growth on conventional GaAs substrates is appealing for a number of communications and sensing applications. We present a new class of GaAs-based quantum well (QW) heterostructure that exploits the unusual impact of Bi and N on the GaAs band structure to produce type-II QWs having long emission wavelengths with little or no net strain relative to GaAs, while also providing control over important laser loss processes. We theoretically and experimentally demonstrate the potential of GaAs1−xBix/GaNyAs1−y type-II QWs on GaAs and show that this approach offers optical emission and absorption at wavelengths up to ~3 µm utilising strain-balanced structures, a first for GaAs-based QWs. Experimental measurements on a prototype GaAs0.967Bi0.033/GaN0.062As0.938 structure, grown via metal-organic vapour phase epitaxy, indicate good structural quality and exhibit both photoluminescence and absorption at room temperature. The measured photoluminescence peak wavelength of 1.72 μm is in good agreement with theoretical calculations and is one of the longest emission wavelengths achieved on GaAs to date using a pseudomorphically grown heterostructure. These results demonstrate the significant potential of this new class of III-V heterostructure for long-wavelength applications.

Giant bowing of the band gap and spin-orbit splitting energy in GaP1−xBix dilute bismide alloys

Bushell

Nattermann

et al. 2019

Sci Rep

Self Cite

Using spectroscopic ellipsometry measurements on GaP 1− x Bi x /GaP epitaxial layers up to x = 3.7% we observe a giant bowing of the direct band gap ( ) and valence band spin-orbit splitting energy (Δ SO ). (Δ SO ) is measured to decrease (increase) by approximately 200 meV (240 meV) with the incorporation of 1% Bi, corresponding to a greater than fourfold increase in Δ SO in going from GaP to GaP 0.99 Bi 0.01 . The evolution of and Δ SO with x is characterised by strong, composition-dependent bowing. We demonstrate that a simple valence band-anticrossing model, parametrised directly from atomistic supercell calculations, quantitatively describes the measured evolution of and Δ SO with x . In contrast to the well-studied GaAs 1− x Bi x alloy , in GaP 1− x Bi x substitutional Bi creates localised impurity states lying energetically within the GaP host matrix band gap. This leads to the emergence of an optically active band of Bi-hybridised states, accounting for the overall large bowing of and Δ SO and in particular for the giant bowing observed for x ≲ 1%. Our analysis provides insight into the action of Bi as an isovalent impurity, and constitutes the first detailed experimental and theoretical analysis of the GaP 1− x Bi x alloy band structure.