Approaching the Hole Mobility Limit of GaSb Nanowires

Abstract

In recent years, high-mobility GaSb nanowires have received tremendous attention for high-performance p-type transistors; however, due to the difficulty in achieving thin and uniform nanowires (NWs), there is limited report until now addressing their diameter-dependent properties and their hole mobility limit in this important one-dimensional material system, where all these are essential information for the deployment of GaSb NWs in various applications. Here, by employing the newly developed surfactant-assisted chemical vapor deposition, high-quality and uniform GaSb NWs with controllable diameters, spanning from 16 to 70 nm, are successfully prepared, enabling the direct assessment of their growth orientation and hole mobility as a function of diameter while elucidating the role of sulfur surfactant and the interplay between surface and interface energies of NWs on their electrical properties. The sulfur passivation is found to efficiently stabilize the high-energy NW sidewalls of (111) and (311) in order to yield the thin NWs (i.e., <40 nm in diameters) with the dominant growth orientations of ⟨211⟩ and ⟨110⟩, whereas the thick NWs (i.e., >40 nm in diameters) would grow along the most energy-favorable close-packed planes with the orientation of ⟨111⟩, supported by the approximate atomic models. Importantly, through the reliable control of sulfur passivation, growth orientation and surface roughness, GaSb NWs with the peak hole mobility of ∼400 cm(2)V s(-1) for the diameter of 48 nm, approaching the theoretical limit under the hole concentration of ∼2.2 × 10(18) cm(-3), can be achieved for the first time. All these indicate their promising potency for utilizations in different technological domains.

Crystalline and oxide phases revealed and formed on InSb(111)B

“…This is the same method we have used previously for preparing crystalline oxidized III–V(100) surfaces 14 , found to reduce the amount of defect states by over an order of magnitude beneath an atomic layer deposition (ALD) grown oxide film 15 and thus enabling efficient passivation. However, the following crucial questions have previously remained unresolved: (i) is the crystalline oxidation possible for other crystal planes; in more general for various crystal faces [not only (100) planes] exposed in nanotechnology 2,7–9,12,16,17 , and (ii) how to produce clean InSb surfaces in an industrially potential way, which is necessary in order to perform the crystalline pre-oxidation in practice. Here we provide solutions to these questions using InSb(111)B as a template for investigations.…”

Impact of doping and diameter on the electrical properties of GaSb nanowires

“…The most common observed trend is a decrease in mobility due to the stronger influence of surface scattering for smaller diameters. 11,12 However, there have also been reports that the diameter has no impact on the mobility for InAs n-type NWs with a diameter >40 nm. 13 Apart from the diameter, doping control, which allows for determining the threshold voltage and reducing access resistances, is also crucial.…”

Recent advances in low‐dimensional semiconductor nanomaterials and their applications in high‐performance photodetectors

“…The illustration shows a corresponding SEM image and a schematic of the device. Reproduced with permission . Copyright 2015, American Chemical Society.…”

“…These parameters of the FETs change as the thickness changes. One‐dimensional semiconductor materials are also potential options for developing high‐performance FETs . A schematic and SEM image of a GaSb NWs FET is shown in Figure D.…”

“…A schematic and SEM image of a GaSb NWs FET is shown in Figure D. Tests of NWs FETs of different diameters have shown that the size has a large effect on the characteristics of the corresponding device . One of the reasons for the greater impact on device performance in FETs of low‐dimensional materials is the interface contact problem.…”