On-chip Fabrication of High Performance Nanostructured ZnO UV Detectors

Abstract

Developing rationally controlled bottom-up device fabrication processes is essential for the achievement of high performance optimal devices. We report a controlled, seedless and site-selective hydrothermal technique to fabricate high-performance nanostructured ZnO UV-detectors directly on-chip. We demonstrate that by controlling the nanowire growth process, via tuning the experimental parameters such as the concentration of reactants and the growth time, and by introducing a refresh of the growth solution, the device structure efficiency can be enhanced to significantly improve its performance. The on-chip fabricated bridging nanosyringe ultraviolet detector demonstrates improved sensitivity (~105), nanowatts detectability, and ultrafast response-time (90 ms) and recovery-time (210 ms). The improvement in response-time and recovery-time is attributed to the unique nanowire-nanowire junction barrier dominated resistance and the direct contact between ZnO and Au electrodes. Furthermore, the enhanced sensitivity and nanowatts detectability of the bridging nanosyringe device are due to the reduction in dimensionality and ultrahigh surface-to-volume ratio. This work paves the way toward low cost, large scale, low temperature, seedless and site-selective fabrication of high performance ZnO nanowire sensors on flexible and transparent substrates.

A Multipurpose CMOS Platform for Nanosensing

“…Specifically, the oxygen ions (O 2− ) naturally adsorbed on the ZnO NW surface will attract the photogenerated holes, while the electrons will contribute to the current in the conduction band [34,35]. Although the assembled NWs have different electrical characteristics, they are both sensitive to the UV light with similar trend.…”

Flexible, transparent, high dielectric and photoconductive thin films using ZnO nanosheets-multi-walled carbon nanotube-polymer nanocomposites

“…ZnO is an important II-VI semiconductor, have been extensively studied in photovoltaics [15,16], photoelectrochemical cells [17], UV detectors [18] , lasers [19], light emitting diodes [20] and gas sensors [21] , due to its unique optical and electrical properties including wide band gap, higher excitonic binding energy, superior electron mobility, low cost, and environmental friendliness. On the other hand, carbon nanotube has many remarkable electrical and physical properties including high carrier transport mobility [22,23], high mechanical strength [24] and excellent chemical stability.…”

Photoluminescence Study of the Influence of Additive Ammonium Hydroxide in Hydrothermally Grown ZnO Nanowires

“…Ammonium hydroxide (NH4OH) has often been employed for the growth of ZnO NWs on Au metal surfaces [30,31]. For instance, in our previous work, we show that NH4OH can be used for simultaneous tuning of the NW density and electrical properties of the ZnO NWs grown on seedless Au surface [32].…”

“…Growth process with an in-situ integration of ZnO NWs over a metal electrode without any ZnO seed layer may improve the charge transport process across the metal-semiconductor (MS) contact interface and, in consequence, may improve device performances [30]. Ammonium hydroxide (NH4OH) has often been employed for the growth of ZnO NWs on Au metal surfaces [30,31].…”