Kang Jeonghun, Lee Jeong Hyuk, Lee Han-Koo, Kim Kwang-Tak, Kim Jin Hyeok, Maeng Min-Jae, Hong Jong-Am, Park Yongsup, Kim Kee Hoon
Center for Novel States of Complex Materials Research, Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea.
Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 37673, Korea.
Materials (Basel). 2022 Mar 25;15(7):2417. doi: 10.3390/ma15072417.
In spite of great application potential as transparent -type oxides with high electrical mobility at room temperature, threading dislocations (TDs) often found in the (Ba,La)SnO (BLSO) films can limit their intrinsic properties so that their role in the physical properties of BLSO films need to be properly understood. The electrical properties and electronic structure of BLSO films grown on SrTiO (001) (STO) and BaSnO (001) (BSO) substrates are comparatively studied to investigate the effect of the TDs. In the BLSO/STO films with TD density of ~1.32 × 10 cm, -type carrier density and electron mobility are significantly reduced, as compared with the BLSO/BSO films with nearly no TDs. This indicates that TDs play the role of scattering-centers as well as acceptor-centers to reduce -type carriers. Moreover, in the BLSO/STO films, both binding energies of an Sn 3 core level and a valence band maximum are reduced, being qualitatively consistent with the Fermi level shift with the reduced -type carriers. However, the reduced binding energies of the Sn 3 core level and the valence band maximum are clearly different as 0.39 and 0.19 eV, respectively, suggesting that the band gap renormalization preexisting in proportion to is further suppressed to restore the band gap in the BLSO/STO films with the TDs.
尽管作为室温下具有高电子迁移率的透明型氧化物具有巨大的应用潜力，但在（Ba，La）SnO（BLSO）薄膜中经常发现的穿透位错（TDs）会限制其本征性能，因此需要正确理解它们在BLSO薄膜物理性能中的作用。对生长在SrTiO（001）（STO）和BaSnO（001）（BSO）衬底上的BLSO薄膜的电学性能和电子结构进行了比较研究，以研究TDs的影响。与几乎没有TDs的BLSO/BSO薄膜相比，在TD密度约为1.32×10 cm的BLSO/STO薄膜中，-型载流子密度和电子迁移率显著降低。这表明TDs起到了散射中心和受主中心的作用，以减少-型载流子。此外，在BLSO/STO薄膜中，Sn 3核心能级和价带最大值的结合能均降低，这与随着-型载流子减少的费米能级移动在定性上是一致的。然而，Sn 3核心能级和价带最大值降低的结合能明显不同，分别为0.39和0.19 eV，这表明与 成比例预先存在的带隙重整化在具有TDs的BLSO/STO薄膜中进一步受到抑制，以恢复带隙。
