Electrodeposited n‐type cuprous oxide cubic nanostructures for liquefied petroleum gas sensing

Abstract

A surfactant free template assisted electrodeposition method was used to fabricate thick n‐type Cu2O films having cubic nanostructures for the detection of liquefied petroleum (LP) gas at low concentrations. Templates were fabricated by initially electrodepositing a p‐type Cu2O thin film on a Ti substrate followed by annealing that changed conductivity type of the film, as confirmed by Mott–Schottky and spectral response measurements. SEM measurements of resulting films showed nano‐cubic crystals having sizes of 150–300 nm. When exposed to a mixture of LP gas and dry air, the resistance of these films increased and the maximum response was recorded when films were maintained at 180 °C for all concentrations and it was independent of the surface morphology. At 180 °C, at the lowest tested LP gas concentration of 2 vol.%, a twofold increase in response was observed in the nano‐cubic films compared to the micro‐crystalline n‐type Cu2O films. This improvement in gas response is attributed to increased effective surface area of these nanostructured films. Compared to other LP gas sensing materials, Cu2O films showed very good response times and recovery times of ∼120 and ∼90 s, respectively.

Surfactant free template assisted electrodeposited n-type nano-cubic Cu2O thin films for nonenzymatic glucose sensing

“…Previous work by Won and Stanciu reports larger cubic crystals in the range of 800 nm–1 µm obtained using chemical bath deposition. The thickness of the films was calculated using Faraday's equation mentioned elsewhere .…”

“…Cu 2 O is a well‐known oxide semiconductor with a direct band gap of ∼2.0 eV and is considered an earth abundant green material with a great potential to be used in many applications such as photovoltaics , gas sensing , electro‐catalysis , and photo‐catalysis . As a semiconductor, the carrier concentration of Cu 2 O is relatively low (∼10 14 –10 15 cm −3 ) .…”

“…Therefore, to maximize the sensor performance, careful attention is required for the optimization of surface morphology in terms of both size and shape. Due to the presence of Cu vacancies in the crystal lattice, Cu 2 O has been generally known as a p‐type semiconductor . However, it has now been established that by employing electrochemical deposition technique, the conductivity of Cu 2 O can be easily controlled to grow both p‐type and n‐type thin films , compared to other fabrication techniques such as facile hydrothermal process , fixure‐reduction method , and wet chemistry synthesis .…”

“…Due to the presence of Cu vacancies in the crystal lattice, Cu 2 O has been generally known as a p‐type semiconductor . However, it has now been established that by employing electrochemical deposition technique, the conductivity of Cu 2 O can be easily controlled to grow both p‐type and n‐type thin films , compared to other fabrication techniques such as facile hydrothermal process , fixure‐reduction method , and wet chemistry synthesis . Additionally, the scalability and the ability to grow films with different surface morphologies are advantages of the electrochemical deposition technique .…”

Effect of pre-surface treatments on p-Cu2O/Au Schottky junctions

“…As a feasible, eco-friendly, affordable, photosensitive semiconductor, Cu 2 O is found in applications in photovoltaics (Camacho-Espinosa et al, 2018), photocatalysts (Singh et al, 2018), water splitting systems (Ma et al, 2015), gas sensors (Jayasingha et al, 2017), glucose sensors (Yu et al, 2018), supercapacitors (Wang et al, 2018) and magnetic storage devices (Hu et al, 2016).…”