Antimony‐Rich GaAs_xSb_1−x Nanowires Passivated by Organic Sulfides for High‐Performance Transistors and Near‐Infrared Photodetectors

Abstract

Due to their excellent properties, ternary GaAsxSb1−x nanowires have been extensively investigated to enable various nanodevice structures. However, the surfactant effect of antimony has a notorious impact on the surface morphology and electrical properties of prepared Sb‐rich nanowires, restricting their practical utilization. Herein, through the in situ passivation effect of thiourea, highly‐crystalline, uniform, and thin GaAsxSb1−x nanowires (x ≤ 0.34) are successfully achieved. In contrast to low‐melting‐point sulfur powders typically used in surfactant‐assisted chemical vapor deposition, thiourea has a relatively higher melting point, facilitating the more controllable formation of SbxSy layer on the nanowire surface to minimize the radial growth and to stabilize the sidewalls for high‐quality Sb‐rich nanowires. When configured into field‐effect transistors, the obtained GaSb nanowires exhibit excellent device performance with a hole mobility of over 200 cm2 V−1 s−1. The optimal GaAs0.18Sb0.82 device yields an impressive responsivity of 5.4 × 104 A W−1 and an external quantum efficiency of 4.4 × 106% under near‐infrared light illumination. Importantly, the rise and decay times are as efficient as 80 and 104 µs, respectively, which are better than any values reported for GaAsSb nanowire photoconductors to date. All these results demonstrate the promising potential of GaAsxSb1−x nanowires for high‐mobility electronics and ultrafast near‐infrared optoelectronics.

Sulfur-Passivated InSb Nanowires for Infrared Photodetectors

“…From the I DS – V GS curve in Figure d, it is also clear that I DS increased with increasing V GS , indicating that electrons dominate the transfer behavior of the S-InSb NW FET. Transconductance ( g m ), a significant parameter of the FET, could be acquired by the following equation ,,− g normalm = normald I normalD normalS / normald V normalG normalS …”

“…From the data in Figure d, the peak value of the transconductance was calculated to be 58.85 nAV –1 . Therefore, the field-effect electron mobility, μ e , of the S-InSb NW-based FET can be acquired using the following equations ,,− C normali ≈ 2 π ε o ε r L In ( 2 h / r ) μ normale = g normalm L 2 false( V normald C normali false) where C i is defined as the back-gate capacitance, ε 0 is the vacuum dielectric constant (ε 0 = 8.85 × 10 –12 F m –2 ), ε r is the relative dielectric constant of SiO 2 (ε r = 3.9), h is the thickness of the SiO 2 dielectric layer (300 nm), L is the S-InSb NW length in the channel (5 μm), and r is the radius of the NW (40.5 nm). The calculated μ e is shown in Figure e, and the peak value of 366.25 cm 2 V –1 s –1 was recognized as the field-effect mobility. , To understand the overall transport performances of our prepared S-InSb NWs, the field-effect mobilities of 30 individual S-InSb NW-based FET devices were randomly counted and the results are shown in Figure f.…”

“…With intriguing properties in terms of high carrier mobility, highly efficient photoelectric conversion, and suitability for braiding array devices, narrow bandgap III–V semiconductor nanowires (NWs) have aroused enormous amounts of research interest. − Among all binary III–V semiconductors, InSb NWs possess the narrowest bandgap (0.17 eV) and the highest electron mobility, along with a large Landé g-factor and strong spin–orbit interactions, making them technologically significant. ,− These materials are deemed to be suitable platforms for the study of topological superconducting quantum devices, Majorana zero modes, high-performance field-effect transistors (FETs), and especially infrared optoelectronic devices. − ,, …”

Artificial Visual Systems With Tunable Photoconductivity Based on Organic Molecule‐Nanowire Heterojunctions

“…Based on the transmission electron microscopy (TEM) images, spherical catalytic seeds are clearly observed at the NW tips (Figure S2a, Supporting Information), where this observation is consistent with the vapor-liquid-solid (VLS) growth mechanism typically known for InGaAs NWs. [33,34] Obvious lattice fringes are witnessed by high-resolution TEM (HRTEM) with a spacing of 0.34 nm between adjacent lattice planes, corresponding to the <111> dominant direction of the InGaAs NWs (Figure 1b). Energy-dispersive X-ray spectroscopy (EDS) was then applied to evaluate the composition of the InGaAs NW, which confirmed the composition of In x Ga 1-x As with x being ≈0.49 (Figure S2b, Supporting Information).…”

Substrate‐Free Chemical Vapor Deposition of Large‐Scale III–V Nanowires for High‐Performance Transistors and Broad‐Spectrum Photodetectors

“…[5,44,47,48] The hysteresis loop caused by the abundant surface states of as-prepared NWs could be further reduced by surface passivation, construction of core-shell NWs and introduction of stress, etc. [49][50][51] Furthermore, the mobility of as-fabricated NWFETs is calculated by using the low-bias (e.g., V DS = 0.1 V) transconductance in the transfer characteristics, g m = (dI DS )/(dV GS )| V DS , and the analytical expression, μ = g m (L 2 /C OX )(1/V DS ), where C OX is the gate capacitance obtained from the finite element analysis software COMSOL with respect to different diameters of NW. [45,52] With the known NW length (in the channel of FET) and diameter, the field-effect mobility of NW can be yielded reliably.…”