Aligned Epitaxial SnO₂ Nanowires on Sapphire: Growth and Device Applications

Abstract

Semiconducting SnO2 nanowires have been used to demonstrate high-quality field-effect transistors, optically transparent devices, photodetectors, and gas sensors. However, controllable assembly of rutile SnO2 nanowires is necessary for scalable and practical device applications. Here, we demonstrate aligned, planar SnO2 nanowires grown on A-plane, M-plane, and R-plane sapphire substrates. These parallel nanowires can reach 100 μm in length with sufficient density to be patterned photolithographically for field-effect transistors and sensor devices. As proof-of-concept, we show that transistors made this way can achieve on/off current ratios on the order of 10(6), mobilities around 71.68 cm(2)/V·s, and sufficiently high currents to drive external organic light-emitting diode displays. Furthermore, the aligned SnO2 nanowire devices are shown to be photosensitive to UV light with the capability to distinguish between 254 and 365 nm wavelengths. Their alignment is advantageous for polarized UV light detection; we have measured a polarization ratio of photoconductance (σ) of 0.3. Lastly, we show that the nanowires can detect NO2 at a concentration of 0.2 ppb, making them a scalable, ultrasensitive gas sensing technology. Aligned SnO2 nanowires offer a straightforward method to fabricate scalable SnO2 nanodevices for a variety of future electronic applications.

Synthesis of SnO2 Nanowires Using SnI2 as Precursor and Their Application as High‐Performance Self‐Powered Ultraviolet Photodetectors

“…It can be seen from Table that most photodetectors with high value of EQE and R λ are measured at bias from 1 to 20 V . The devices fabricated from SnO 2 nanowires, ZnO‐Nanorod/CuSCN, TiO 2 nanorod arrays and Ag‐ZnO nanowires measured at nominal zero bias show low values of EQE and R λ . However, the individual SnO 2 nanowire‐based photodetectors D1 and D2 in the present work show both high performances and self‐powered properties.…”

Micro/Nano Gas Sensors: A New Strategy Towards In-Situ Wafer-Level Fabrication of High-Performance Gas Sensing Chips

“…In comparison with other strategies of the fabrication of MOS gas sensors with microhotplatforms and nano-sized SnO 2 as a sensitive material1516171831323335, our strategy is of lower cost, batch production, and more controllability. Not only the size, sensitive material, and doped catalysts can be well controlled, but the working temperature, sensitivity, and detection limit can be also controlled.…”

“…Due to these distinct advantages, much effort has geared towards the fabrication process of such nanostructured gas sensing materials. Many nanostructured materials such as nanoparticles45, nanotubes678910, nanowires111213141516171819, and hollow spheres202122 have been extensively researched for various gas sensing applications. In particular, nanostructured materials of metal oxide semiconductor (MOS), which possess remarkably high sensitivity and a large detection range to a variety of gases23, have been widely researched in recent decades and are expected to be deployed in domestic, industries, aerospace, and military applications6242526272829.…”

Guided Growth of Horizontal Single-Wall Carbon Nanotubes on M-Plane Sapphire

“…18 For the C-plane, which has higher symmetry, the 6-fold symmetric alignment is the same for ZnO 16 and GaN 17 NWs; however, no alignment was reported for CNTs. It was suggested that this is due to the high symmetry of C-plane sapphire, 10 which presumably does not produce strong enough anisotropy.…”