Hydrothermal synthesis porous silicon/tungsten oxide nanorods composites and their gas-sensing properties to NO2 at room temperature

Low-Temperature Photochemically Activated Amorphous Indium-Gallium-Zinc Oxide for Highly Stable Room-Temperature Gas Sensors

“…To operate metal oxide gas sensors at a low temperature, several methods have been developed, including: modified porous nanostructured materials, utilization of nanosized particles, , hybridization with an organic sensing layer, and ultraviolet–visible (UV–vis) light-induced activation during sensor operation. − Among these approaches, the photoactivation approach appears particularly promising, as the sensor can be operated at room temperature and a low-power single UV light-emitting diode (LED) can be used as a light source. − In previous studies on photoactivated gas sensors, however, conventional sensing materials such as nanocrystalline or polycrystalline SnO 2 , TiO 2 , ZnO (or their complexes) have been commonly used. However, these may not show a sufficiently high sensitivity, because of their low conductivity (determined by their intrinsic carrier mobility and grain boundary effects), and insufficient photocurrent generation by UV irradiation.…”

Synthesis and characterization of porous silicon as hydroxyapatite host matrix of biomedical applications

“…Porous silicon (PS), since its discovery [ 1 – 4 ], has had huge development for various applications, like gas sensors [ 5 ], solar cells [ 6 , 7 ], Bragg reflectors [ 8 ], biosensors [ 9 – 12 ], photocatalysis [ 13 ], tissue engineering [ 14 ], and cell growth [ 15 – 18 ], among others. Particularly, the last two applications have attracted researcher interest in studying the properties of PS as a host matrix Hydroxyapatite (HA) and its implementation in the development of processes leading to bone regeneration.…”

Nanosilicon-Based Composites for (Bio)sensing Applications: Current Status, Advantages, and Perspectives

“…), which play a crucial role for the effective detection of (bio)molecules. Mainly, MOx nanolayers/nanoparticles can be deposited over a nano-Si surface through the following techniques: (i) RF and DC magnetron sputtering [24,34,36,37,120,121,123,124,125,126]; (ii) sol–gel/hydrothermal synthesis + spin coating [17,26,127,128,129,130,131]; (iii) drop casting technique + pulsed laser ablation in liquid [132]; (iv) vapor–liquid–solid growth and chemical vapor deposition [25,40,133]; (v) catalytic immersion method [134]; and (vi) electrochemical and chemical deposition [35,122,135].…”

“…It has been ascertained that silicon/MOx nanocomposites are widely used for gas detection through the I–V curve characterization [136], resistance [24,34,35,37,39,120,121,122,124,125,126,129,131,133,135,137,138], and capacitance [25,40] measurements. Generally, the main gas sensing mechanism is based on oxygen adsorption on the nano-Si/ MOx surface, causing electron extraction from the conductive band of semiconductors.…”

“…A number of works have also been published on the p-n heterojunction by using a combination of p-type PSi and n-type ZnO [24,35,36,122,125,134], WO 3 [36,129,137,138,139], SnO 2 [122,133], V 2 O 5 [37], and TiO 2 [120]. The sensitivity of these nanocomposites was enhanced in comparison to the bare semiconductors and this can be explained as follows [120]: (a) a reduction in the surface activation energy E a upon the formation of the p-n heterojunction, resulting in increased analyte adsorption; (b) the presence of oxygen species and dangling bonds on PSi/MOx, and as a consequence, more reaction sites on the surface, which improved the adsorption of target molecules.…”