Ga2O3(Sn) Oxides for High-Temperature Gas Sensors

Abstract

Gallium(III) oxide is a promising functional wide-gap semiconductor for high temperature gas sensors of the resistive type. Doping of Ga2O3 with tin improves material conductivity and leads to the complicated influence on phase content, microstructure, adsorption sites, donor centers and, as a result, gas sensor properties. In this work, Ga2O3 and Ga2O3(Sn) samples with tin content of 0–13 at.% prepared by aqueous co-precipitation method were investigated by X-ray diffraction, nitrogen adsorption isotherms, X-ray photoelectron spectroscopy, infrared spectroscopy and probe molecule techniques. The introduction of tin leads to a decrease in the average crystallite size, increase in the temperature of β-Ga2O3 formation. The sensor responses of all Ga2O3(Sn) samples to CO and NH3 have non-monotonous character depending on Sn content due to the following factors: the formation of donor centers and the change of free electron concentration, increase in reactive chemisorbed oxygen ions concentration, formation of metastable Ga2O3 phases and segregation of SnO2 on the surface of Ga2O3(Sn) grains.

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

“…The modern theoretical studies indicate that the former case is more likely to be the cause of band gap narrowing [34]. Considering the gas sensing properties shallow donor levels, associated with the Nb Ga defects, should positively affect the free charge carrier concentration, which might be beneficial for oxygen chemisorption on the materials surface and, as a result, for the gas sensor response itself [27][28][29][30]. The increase in the annealing temperature causes the growth of the band gap to increase the levels, corresponding to the bulk β-Ga 2 O 3 crystal.…”

“…The latter strategy may be considered as the most beneficial as the introduction of the second phase, either metal oxide or noble metal, in the materials structure can compromise the desired long-term stability of material and reliability of manufacturing process [25,26]. Doping of Ga 2 O 3 with n-type donor dopants-Sn, Ti and Si-has been reported to improve its electrical and gas sensing properties towards both oxidating and reducing gases due to activation of oxygen surface chemisorption [27][28][29][30]. Other n-type dopants have been reported in experimental and theoretical studies to drastically improve electrical properties of Ga 2 O 3 , valuable in semiconductor industry [31][32][33].…”

P-type Inversion at the Surface of β-Ga2O3 Epitaxial Layer Modified with Au Nanoparticles

“…The properties of gallium oxide β-Ga 2 O 3 , such as ultrawide bandgap, high breakdown voltage, high carrier mobility, and chemical and thermal stability; and the fact that high quality bulk crystals (and therefore also monocrystalline substrates) can be fabricated with melt-growth methods [1,2] predestine β-Ga 2 O 3 to be the material of choice for high power and high frequency electronic devices [3], solar-blind photodetectors [4,5], UV emitters, transparent conductive films, and gas sensors [6,7]. However, due to its electric properties, p-type doping of β-Ga 2 O 3 still remains a challenge [2].…”

Газочувствительные свойства пленок твердого раствора In-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=--Ga-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=-

“…DOI: 10.21883/PJTF.2022. 14.52869.19211 Пленки полупроводниковых оксидов металлов широко применяются в газовых сенсорах [1,2]. Традиционно используются оксиды как n-типа проводимости (SnO 2 , ZnO, TiO 2 , α-Fe 2 O 3 , WO 3 ), так и p-типа (CuO, NiO, Cr 2 O 3 , Co 3 O 4 ).…”