Thermoelectric Properties of Hot-pressed Boron Suboxide (B<SUB>6</SUB>O)

Abstract

Boron suboxide (B 6 O) sintered bodies were prepared by a solid state reaction and a hot pressing method. The thermoelectric properties of B 6 O were compared with those of B 4 C. The electrical conductivity was smaller than that of B 4 C, and the Seebeck coefficient was twice as large as that of B 4 C indicating p-type conduction. The hopping conduction of electronic charge carriers was suggested from the temperature dependencies of the electrical conductivity and mobility. The thermal conductivity was greater than that of B 4 C. The thermoelectric dimensionless figure-of-merit increased with increasing temperature, and was 0.62 × 10 −3 at 1000 K. This value was almost in agreement with that of B 4 C.

Electronic structure and defect properties of B6O from hybrid functional and many-body perturbation theory calculations: A possible ambipolar transparent conductor

“…In terms of impurities, our results suggest that typical doping schemes do not apply to B 6 O due to the unique bonding environment exhibited by the underlying icosahedral structure [13,14], with the majority of substitutional and interstitial impurities acting as deep donors or acceptors. However, we do identify a complex consisting of H and C substituting on the oxygen site that acts as a shallow acceptor and is likely responsible for the observed p-type conductivity in this oxide semiconductor [12]. Our results confirm B 6 O to be a plausible candidate for a p-type TCO and additionally show implications for ambipolar doping if the stoichiometry and background impurity concentration can be controlled.…”

“…The screening found that this compound exhibits a low hole effective mass (around 0.6 compared to >2 for current Cu-based p-type TCOs such CuAlO 2 [7], CuCrO 2 [8], or SrCu 2 O 2 [9]) and a large band gap (3 eV according to G 0 W 0 computations). Boron suboxide has mainly been studied as a hard coating material [10,11] and we are aware of only one paper that measured its transport properties [12]. While Akashi et al concluded that B 6 O can be p-type as-grown, their samples were largely porous and may not accurately reflect the fundamental bulk properties [12].…”

“…Boron suboxide has mainly been studied as a hard coating material [10,11] and we are aware of only one paper that measured its transport properties [12]. While Akashi et al concluded that B 6 O can be p-type as-grown, their samples were largely porous and may not accurately reflect the fundamental bulk properties [12].…”

Identification and design principles of low hole effective mass p-type transparent conducting oxides

“…Whereas none of our candidates have ever been tested (or even suggested) as TCOs, doping studies indicating p -type dopability have already been reported experimentally or computationally for several of them. B 6 O has been experimentally measured to show p -type conductivity31. It has been demonstrated experimentally that PbZr 0.5 Ti 0.5 O 3 can be grown as p -type32, but some recent computations on PbTiO 3 seem to indicate an oxygen vacancy low in energy even in oxidizing conditions33.…”

Nanotwinned Boron Suboxide (B6O): New Ground State of B6O

“…The synthesis procedure is described in detail elsewhere 1 . The TEM specimens were prepared by gently crushing and the B 6 O fragments were dispersed on the holey carbon films coated copper grids.…”