Improved Electron Mobility of AlInSb/InAsSb/AlInSb Heterostructures Grown Lattice-Mismatched on GaAs Substrates

Abstract

We have improved the electron mobility of Al x In1-x Sb/InAs y Sb1-y /Al x In1-x Sb heterostructures grown by molecular beam epitaxy. By using Al0.15In0.85Sb as high-resistivity barrier layers and by using InAs y Sb1-y (whose composition was chosen to be lattice-matched with the Al0.15In0.85Sb) as a channel layer, high electron mobility exceeding 24,000 cm2·V-1·s-1 was obtained at room temperature. This value is an order of magnitude larger than that of an Al0.15In0.85Sb/InSb/Al0.15In0.85Sb lattice-mismatched heterostructure grown as a reference. Mobility is improved by using an InAs y Sb1-y channel because the lattice-mismatch between the barrier and channel layers is minimized.

InAsSb Quantum Dots Grown on GaAs Substrates by Molecular Beam Epitaxy

“…InAsSb is a very attractive material for both electrical and optical application because of its high mobility and small energy gap. [1][2][3][4] Its band gap depends on its antimony content and, at an antimony content of approximately 0.65, reaches a minimum of approximately 0.11 eV, which is approximately half the band gap of InSb. Furthermore, its lattice constant is 2.3% smaller than that of InSb.…”

Increased electron mobility of InAsSb channel heterostructures grown on GaAs substrates by molecular beam epitaxy

“…and was sufficient to prevent parallel conduction in the buffer layer. 6,9 The InAs y Sb 1Ϫy channel thickness, L z , was fixed at 20 nm, enough to accumulate the electrons in the channel. The electron mobility and sheet electron concentration as a function of the As-shutter duty cycle ͑i.e., As content y͒ are shown in Fig.…”

“…We recently reported that the Al content of Al x In 1Ϫx Sb must be at least 0.15 to achieve a highly resistive barrier layer. 6 The electron mobility of an Al 0.15 In 0.85 Sb/InSb/Al 0.15 In 0.85 Sb heterostructure ͑InSb thickness: 20 nm͒ was, however, only 2 120 cm 2 V Ϫ1 s Ϫ1 , even though the InSb thickness was below the critical layer thickness ͑CLT͒ of 32 nm. 6,7 To avoid the problem of lattice strain, we grew Al 0.15 In 0.85 Sb/InAs y Sb 1Ϫy /Al 0.15 In 0.85 Sb heterostructures with reduced lattice mismatch and achieved a high electron mobility exceeding 28 000 cm 2 V Ϫ1 s Ϫ1 at RT.…”

“…6 The electron mobility of an Al 0.15 In 0.85 Sb/InSb/Al 0.15 In 0.85 Sb heterostructure ͑InSb thickness: 20 nm͒ was, however, only 2 120 cm 2 V Ϫ1 s Ϫ1 , even though the InSb thickness was below the critical layer thickness ͑CLT͒ of 32 nm. 6,7 To avoid the problem of lattice strain, we grew Al 0.15 In 0.85 Sb/InAs y Sb 1Ϫy /Al 0.15 In 0.85 Sb heterostructures with reduced lattice mismatch and achieved a high electron mobility exceeding 28 000 cm 2 V Ϫ1 s Ϫ1 at RT. We also grew Al 0.5 Ga 0.5 Sb/InAs y Sb 1Ϫy /Al 0.5 Ga 0.5 Sb heterostructures with minimized lattice mismatch and confirmed that the mobility was improved by reducing the lattice mismatch between the channel layer and the barrier layer.…”