Indications of strong neutral impurity scattering in Ba(Sn,Sb)O3single crystals

Abstract

It was recently discovered that a transparent n-type (Ba,La)SnO 3 system has electrical mobility as high as 320 cm 2 V −1 s −1 at room temperature and superior thermal stability up to ∼500 • C. To understand comparatively the carrier-scattering mechanism in the doped BaSnO 3 , we investigate the physical properties of the single crystals of BaSn 1-x Sb x O 3 (x = 0.03, 0.05, and 0.10), which also show the n-type characters via the Sn site doping by Sb. Transmittance of the grown single crystals in the visible spectral region turn out to be similar to that of the (Ba,La)SnO 3 system, maintaining optical transparency. Temperature-dependent Hall effect measurements reveal that the electrical mobility at room temperature reaches as high as 79.4 cm 2 V −1 s −1 at a carrier density of 1.02 × 10 20 cm −3 , and upon increasing carrier density further, it systematically decreases nearly proportional to the inverse of the carrier density. The overall reduced mobility of the Ba(Sn,Sb)O 3 system as compared to the (Ba,La)SnO 3 system is attributed to the enhanced scattering caused by the Sb ions located in the direct conduction path. Based on the inverse proportionality between the carrier density and the electrical mobility, we suggest that the neutral impurity scattering becomes particularly strong in the Ba(Sn,Sb)O 3 .

Thermopower modulation clarification of the intrinsic effective mass in transparent oxide semiconductor BaSnO3

“…Generally, the τ value of epitaxial films is smaller than that of the bulk single crystal due to the fact that the carrier electrons are scattered at dislocations, which originated from the lattice mismatch (δ) and at other structural defects, in addition to optical phonon scattering. [12], and experimental values of 3.7m 0 [13], 0.61m 0 [14], ∼0.35m 0 [15], ∼0.396m 0 [16], 0.27 ± 0.05m 0 [10], 0.19 ± 0.01m 0 [8]). Consequently, determining the intrinsic m * value is almost impossible.…”

Structure and transport in high pressure oxygen sputter-deposited BaSnO3−δ

“…10,11,[13][14][15] The latter has led to mobilities as high as 70 cm 2 V −1 s −1 at 10 20 cm −3 in relatively thick epitaxial films, doped n-type by substitution with La (for Ba) 9,10,14 or Sb (for Sn). 13,16 The fundamental understanding of BSO has also improved, including its electronic structure in bulk, 10,[17][18][19][20][21][22] as well as its phonon spectrum, 17 optical properties, 10,11,17,[20][21][22]26 scattering mechanisms, 10,[13][14][15]27 defects, 28 and thermal stability. 9 It is understood that the conduction band is derived from Sn 5s states 10,[17][18][19][20][21][22][23][24][25] and progress is being made in identifying mobility-limiting mechanisms in crystals [9][10][11] and films.…”

“…9 It is understood that the conduction band is derived from Sn 5s states 10,[17][18][19][20][21][22][23][24][25] and progress is being made in identifying mobility-limiting mechanisms in crystals [9][10][11] and films. 9,10,[13][14][15]27 There remain a number of unresolved issues, however, including the optimal choice of dopant ion and site 13 and the relative importance of phonon, 11,17 neutral impurity, ionized impurity, 9,10,27 and dislocation scattering. [13][14][15] The latter is significant in films because of the dislocations accommodating the lattice mismatch with the substrate, due to the dearth of perovskite substrates around the 4.116 Å BSO lattice parameter.…”

Transparent Perovskite Barium Stannate with High Electron Mobility and Thermal Stability

“…At least half of the Sb dopants were activated at room temperature to behave as Sb 5+ and to provide extra electron carriers (66). As summarized in Figure 2, the μ of BSSO single crystals reached ∼79 cm 2 V −1 s −1 at n = 1.0 × 10 20 cm −3 , and upon further increases in n, μ systematically (66).…”

“…Motivated by the dispersive conduction band of BaSnO 3 (Figure 1b), our group first tried to grow single crystals of electron-doped BaSnO 3 (31). In 2010 and 2011, we successfully grew BaSnO 3 (66), BLSO (60), and BSSO (66) We obtained (Ba,La)SnO 3 single crystals with a typical size of ∼2 × 2 × 2 mm 3 and a maximum size of 5 × 3 × 1 mm 3 . Most importantly, using electron probe microanalysis (EPMA), we could not observe any Cu-related impurities in the grown BaSnO 3 crystals (60).…”