Gas-sensing behaviour of ZnO/diamond nanostructures

Abstract

Microstructured single- and double-layered sensor devices based on p-type hydrogen-terminated nanocrystalline diamond (NCD) films and/or n-type ZnO nanorods (NRs) have been obtained via a facile microwave-plasma-enhanced chemical vapour deposition process or a hydrothermal growth procedure. The morphology and crystal structure of the synthesized materials was analysed with scanning electron microscopy, X-ray diffraction measurements and Raman spectroscopy. The gas sensing properties of the sensors based on i) NCD films, ii) ZnO nanorods, and iii) hybrid ZnO NRs/NCD structures were evaluated with respect to oxidizing (i.e., NO2, CO2) and reducing (i.e., NH3) gases at 150 °C. The hybrid ZnO NRs/NCD sensor showed a remarkably enhanced NO2 response compared to the ZnO NRs sensor. Further, inspired by this special hybrid structure, the simulation of interaction between the gas molecules (NO2 and CO2) and hybrid ZnO NRs/NCD sensor was studied using DFT calculations.

Improved electrical transport properties of an n-ZnO nanowire/p-diamond heterojunction

“…Cu 2 O, 16 GaN, 17 graphene, 18 NiO, 7 B-doped diamond lm (BDD) [19][20][21][22] and organic materials, 23 have been exploited as the candidate to replace p-type ZnO semiconductors for the fabrication of pn heterojunctions. Among them, the B-doped diamond lm (bandgap 5.47 eV) is appropriate as a hightemperature p-type conductive material.…”

Ultraviolet Photoactivated Room Temperature NO2 Gas Sensor of ZnO Hemitubes and Nanotubes Covered with TiO2 Nanoparticles

“…All the measurements were performed in a closed chamber with the relative humidity (RH) of 50 ± 20% and the temperature of 20.0 ± 10.0 • C (RT), which was maintained at the same humidity and temperature with the normal indoor condition. The electrical resistance of the sensor devices was measured by a source meter (Keithley 2400, Keithley Instruments Inc., Solon, OH, USA) in constant-current operation using a computer-controlled measurement system with the UV illumination (approximately 2.0 W) [21,22]. A custom written LabView program was used, which allowed temperatures and gas-flow rates to be automatically controlled by a computer.…”

Microscopic Study of Bovine Serum Albumin Adsorption on Zinc Oxide (0001) Surface

“…Zinc oxide (ZnO) is a semiconductor material that can be prepared in various forms and sizes and it is commonly available commercially. It is well known as a material for transparent conductive electrodes and light‐emitting [ 2 ] and gas‐sensor devices [ 3 ] as well for its photocatalytic [ 4 ] and bactericidal properties, [ 5 ] in particular in nanoparticle form. ZnO nanomaterials can be prepared by various methods, from magnetron sputtering, [ 6 ] wet chemical synthesis on substrates [ 1,7 ] and in solutions [ 8 ] to green eco‐friendly approaches.…”

“…The mutual interaction of ZnO nanomaterials and biological environment can manifest itself in various ways and can be very specific for particular material and its surface modification. [ 8 ] The surface, shape, size, and doping effects of ZnO provided opportunities for various gas sensors [ 3 ] or biosensors. [ 11 ] Free carrier concentration in ZnO can be significantly increased and photoluminescence altered by hydrogen plasma treatment.…”