O₂ sensing dynamics of BiFeO₃ nanofibers: effect of minor carrier compensation

Abstract

In this paper we investigate O(2) sensing dynamics in BiFeO(3) (BFO) nanofibers at various concentrations and temperatures, by using a combined experiment and computer simulation approach. Samples of pristine BFO, Ni-doped BFO, and Pb-doped BFO nanofibers were prepared. By incorporating Ni and Pb, additional acceptor states are introduced in BFO. Density functional theory calculations show that Ni prefers to substitute Fe site while Pb substitutes Bi site, resulting in a new deep donor originating from Ni interstitial defects, along with oxygen vacancies (V(o)). We find that both the sensing response and recovery time are shorter in samples made of pristine BFO nanofibers than in Ni- and Pb-doped nanofiber samples. We interpret the observed sensing dynamics through charge transport theory of the major (acceptors) and minor (donors) carriers, and found that the minor carrier compensation plays a significant role in determining the response and recovery time of the sensor device. This minor carrier compensation charge transport mechanism will provide new insights into more robust sensor development strategies, and into the research of ion-electron coupling in chemical dynamics of semiconductors.

Selective Improvement of NO2 Gas Sensing Behavior in SnO2 Nanowires by Ion-Beam Irradiation

“…The above observations, related to the sensing recovery in Figure 6c, are consistent with the proposed defect structures where Sn vacancies and Sn interstitials are located inside and on the crystal surfaces, respectively. As reported recently, 58,59 the recovery process is governed by the transport of minor carriers (or the holes from Sn vacancies in this study). For unirradiated samples, due to the deep acceptor (Sn vacancy) level, the recovery time is long (i.e., 1017 s).…”

Orientation Dependence of Elastic and Piezoelectric Properties in Rhombohedral BiFeO3

“…The Curie point and the antiferromagnetic Neel point of BiFeO 3 are 1100 [3] and 640 K [4], respectively. Below the Curie point, BiFeO 3 is a member of rhombohedral crystal system with point group of 3m [18].…”

“…Bismuth ferrite (BiFeO 3 ) was first actively pursued as a room temperature single-phase multiferroic material for its coexistence of magnetic order and electric order, high Curie point, and G-type antiferromagnetic Neel point [1,2,3,4]. Then, as BiFeO 3 exhibits good ferroelectric and piezoelectric properties, it was also studied as a piezoelectric phase to combine other magnetostrictive phase to form composite multiferric with tailored properties, such as BiFeO 3 -CoFe 2 O 4 [5], BiFeO 3 -CuFe 2 O 4 [6], etc., which shows potential technical applications in multi-state magnetoelectric memories [7], weak magnetic fields detectors [8], and other novel sensors [9,10].…”

Electrical and magnetic properties of spherical SmFeO 3 synthesized by aspartic acid assisted combustion method

“…However, it can be seen that the order of carrier concentration is 10 -6 for all temperatures. The higher carrier concentration at 350 o C is mainly due to excess oxygen species adsorbed on the surface of the active material increasing the number of acceptor levels [37][38][39][40][41]. Further, the observed decrease in carrier concentration is due to desorption of excess oxygen species on the surface at elevated temperature; the constant carrier concentration from 400 o C implies a complete absence of oxygen above this temperature [38].…”