Electrical and Gas Sensor Properties of Nb(V) Doped Nanocrystalline β-Ga 2 O 3 .

A flame spray pyrolysis (FSP) technique was applied to obtain pure and Nb(V)-doped nanocrystalline β-Ga 2 O 3 , which were further studied as gas sensor materials. The obtained samples were characterized with XRD, XPS, TEM, Raman spectroscopy and BET method. Formation of GaNbO 4 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-Ga 2 O 3 . Superior gas sensor performance of obtained ultrafine materials at lower operating temperatures compared to previously reported thin film Ga 2 O 3 materials is shown.