Bandgap and composition of bulk InAsSbBi grown by molecular beam epitaxy

Abstract

The structural and optical properties of pseudomorphic InAsSbBi grown on GaSb are examined using reflection high-energy electron diffraction, X-ray diffraction, Rutherford backscattering spectrometry, and spectroscopic ellipsometry. The layer studied is 210 nm thick and was grown by molecular beam epitaxy at 280 °C under a (2 × 3) surface reconstruction using near-stoichiometric fluxes. The material is homogeneous and single crystal with no observable defects or surface Bi droplets. The group-V mole fractions are determined using Rutherford backscattering measurements of the Bi mole fraction and X-ray diffraction measurements of the lattice tetragonal distortion. The bandgap energy is determined from the room temperature optical constants measured using spectroscopic ellipsometry. These and measurements from pseudomorphic InAsSb and InAsBi on GaSb are utilized to describe the bandgap energy of InAsSbBi as a function of mole fraction using a bandgap bowing model.

Intrinsic point defects and the n - and p -type dopability of the narrow gap semiconductors GaSb and InSb

“…20,21 Moreover, GaSb and InSb have both been demonstrated to incorporate N and Bi effectively, resulting in a reduction in band gap [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] in a similar manner to the more widely studied, GaAs-based dilute nitrides and bismides. 39,40 Alloys can be produced of GaAs, GaSb and InSb, together with the relevant nitrides and/or bismides to tune the optical and electronic properties for a variety of applications; [41][42][43][44][45] indeed, very high efficiency tandem solar cells include an active layer composed of such an alloy. 46 Given the importance of GaSb and InSb, there are surprisingly few studies on their intrinsic defect properties, which are key to their dopability and hence functionality in devices.…”

Гетероструктуры Ga-=SUB=-x-=/SUB=-In-=SUB=-1-x-=/SUB=-As-=SUB=-y-=/SUB=-Bi-=SUB=-z-=/SUB=-Sb-=SUB=-1-y-z-=/SUB=-/InSb для фотоприемных устройств (λ = 6-12 μm)

“…Возможность получения положительного эффекта с Bi была подтверждена экспериментально на примере выращенных эпитаксиальных слоев InAsBiSb на InSb [3][4][5][6]. Однако в данном случае в качестве лимитирующих технологических факторов выступают ограничение растворимости висмута в растворах-расплавах A 3 B 5 и рост числа структурных дефектов, обусловленных различием подложки и слоя по параметрам решетки и коэффициенту термического расширения (КТР).…”

Examination of the Structural Quality of InAsSbBi Epilayers using Cross Section Transmission Electron Microscopy

“…Efficient infrared detection and emission is desired for numerous applications, including navigation, night vision, communications, imaging, spectroscopy, and launch detection. Incorporation of bismuth in InAs alloys results in larger bandgap reduction per unit strain than antimony and provides an efficient means of tuning the bandgap while limiting the level of biaxial strain that can introduce defects that reduce optical quality [1]. Pseudomorphic InAsSbBi grown on GaSb is of interest because it permits the designer to independently adjust bandgap and strain by varying the group-V mole fractions as well as providing improved hole confinement over InAsSb alone.…”