Electrical and Gas Sensor Properties of Nb(V) Doped Nanocrystalline β-Ga2O3

Abstract

A flame spray pyrolysis (FSP) technique was applied to obtain pure and Nb(V)-doped nanocrystalline β-Ga2O3, which were further studied as gas sensor materials. The obtained samples were characterized with XRD, XPS, TEM, Raman spectroscopy and BET method. Formation of GaNbO4 phase is observed at high annealing temperatures. Transition of Ga(III) into Ga(I) state during Nb(V) doping prevents donor charge carriers generation and hinders considerable improvement of electrical and gas sensor properties of β-Ga2O3. Superior gas sensor performance of obtained ultrafine materials at lower operating temperatures compared to previously reported thin film Ga2O3 materials is shown.

Advanced Flame Spray Pyrolysis (FSP) Technologies for Engineering Multifunctional Nanostructures and Nanodevices

“…Despite these alterations, Nb(V) doping does not significantly enhance the gas-sensing properties of β-Ga 2 O 3 . The best sensor response is observed with 1 mol% Nb(V) doped Ga 2 O 3 after annealing at 900 • C for 24 h. These samples excel in gas and VOC detection (H 2 , CH 4 , acetone) and offer improved long-term performance [241].…”

“…This enhanced H 2 S detection was attributed to the combined effects of catalytic Rh dopants and the active interfaces between graphene and Rh-doped SnO 2 [240]. Utilizing the FSP method, ultrafine β-Ga 2 O 3 nanomaterials with a grain size of 6-12 nm and a surface area above 100 m 2 /g are produced [241]. Introducing Nb(V) during synthesis results in its integration into the β-Ga 2 O 3 lattice but annealing above 800 • C forms a separate GaNbO 4 phase.…”