Strain-engineered allotrope-like bismuth nanowires for enhanced thermoelectric performance

Semimetal to semiconductor transition in $\text{Bi}/\text{TiO}_{2}$ core/shell nanowires

“…However, the practical implementation of Bi nanowires with such small diameters into applications can be challenging. For this reason, Bi-based core/shell nanowires have raised attention in recent years because of their increased thermoelectric performance for relatively large diameters (d > 300 nm) [9][10][11]. Tellurium (Te) coated as shell on the Bi nanowire core can cause a semimetal to semiconductor transition due to the lattice mismatch of the Bi core and the Te shell [10,11].…”

“…For this reason, Bi-based core/shell nanowires have raised attention in recent years because of their increased thermoelectric performance for relatively large diameters (d > 300 nm) [9][10][11]. Tellurium (Te) coated as shell on the Bi nanowire core can cause a semimetal to semiconductor transition due to the lattice mismatch of the Bi core and the Te shell [10,11]. An increased Seebeck coefficient and a reduced thermal conductivity can be the result of such a heterostructure.…”

“…The single crystalline Bi core was prepared by means of the on-film formation of nanowires (OFFON) method as reported in Ref. [9][10][11]16]. Bi thin films were deposited by radio frequency sputtering on SiO 2 /Si substrates.…”

“…Bi thin films were deposited by radio frequency sputtering on SiO 2 /Si substrates. The sputtering system was evacuated to 10 −7 Torr before the deposition [11]. The vacuum was maintained during the sputtering under a 2-mTorr Ar environment at a temperature of 300 K [11].…”

“…The sputtering system was evacuated to 10 −7 Torr before the deposition [11]. The vacuum was maintained during the sputtering under a 2-mTorr Ar environment at a temperature of 300 K [11]. After the deposition process, a heat treatment of the Bi thin films was conducted for several hours at 523 K in a vacuum of 10 −7 Torr [11].…”