TY - JOUR

T1 - Transport properties of (Bi, Sb)2Te3 topological insulator crystals with lateral p-n junction

AU - Golyashov, V. A.

AU - Kokh, K. A.

AU - Tereshchenko, O. E.

N1 - The research was funded by the Ministry of Science and Higher Education of the Russian Federation, Grant No. 075-15-2020-797 (13.1902.21.0024). Публикация для корректировки.

PY - 2023/12

Y1 - 2023/12

N2 - High-quality low-bulk-carrier-concentration 3D topological insulator crystals and films are required for the majority of their potential applications. Creating a p-n transition using composition grading is one of the ways to obtain compensated regions in the bulk of 3D topological insulator crystals. Eventual formation of a p-n junction in 3D topological insulator surface states is expected to enhance the surface-transport-related spin filtering and charge-to-spin conversion. Here we report a detailed study of the transport and surface electronic structure of composition-graded Bi2Te3 and Bi1.34Sb0.66Te3 single crystals with built-in lateral p-n transition. The defect compensation naturally achieved at the p-n interface results in a strong reduction of the bulk carrier concentrations in both crystals. In the Bi2Te3 crystal a high-mobility n-type conductivity region is formed with electron Hall mobility of 70 000 cm2V-1s-1 and Hall concentration of 2×1018cm-3 at 4.2 K. In the Bi1.34Sb0.66Te3 crystal the region of intrinsic conductivity with the lowest observed hole Hall concentration of 6×1017cm-3 and hole Hall mobility of 10 000 cm2V-1s-1 is formed in the vicinity of the p-n junction. The downward band bending was observed on the surface of the p-type conductivity region of the Bi2Te3 and Bi1.34Sb0.66Te3, providing an almost barrierless topological surface state electron channel with no topological p-n junction formed. The composition grading can be used as a reliable method of obtaining high-quality single crystals with relatively large areas of low bulk carrier concentrations and enhanced charge carrier mobility, which can be used in further nanoscale topological insulator device fabrication.

AB - High-quality low-bulk-carrier-concentration 3D topological insulator crystals and films are required for the majority of their potential applications. Creating a p-n transition using composition grading is one of the ways to obtain compensated regions in the bulk of 3D topological insulator crystals. Eventual formation of a p-n junction in 3D topological insulator surface states is expected to enhance the surface-transport-related spin filtering and charge-to-spin conversion. Here we report a detailed study of the transport and surface electronic structure of composition-graded Bi2Te3 and Bi1.34Sb0.66Te3 single crystals with built-in lateral p-n transition. The defect compensation naturally achieved at the p-n interface results in a strong reduction of the bulk carrier concentrations in both crystals. In the Bi2Te3 crystal a high-mobility n-type conductivity region is formed with electron Hall mobility of 70 000 cm2V-1s-1 and Hall concentration of 2×1018cm-3 at 4.2 K. In the Bi1.34Sb0.66Te3 crystal the region of intrinsic conductivity with the lowest observed hole Hall concentration of 6×1017cm-3 and hole Hall mobility of 10 000 cm2V-1s-1 is formed in the vicinity of the p-n junction. The downward band bending was observed on the surface of the p-type conductivity region of the Bi2Te3 and Bi1.34Sb0.66Te3, providing an almost barrierless topological surface state electron channel with no topological p-n junction formed. The composition grading can be used as a reliable method of obtaining high-quality single crystals with relatively large areas of low bulk carrier concentrations and enhanced charge carrier mobility, which can be used in further nanoscale topological insulator device fabrication.

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85180552207&origin=inward&txGid=92d15405b07e34cf9a64159b5edc8bb9

UR - https://www.mendeley.com/catalogue/8324d5c6-f1e6-3325-8504-b09d640a99ef/

U2 - 10.1103/PhysRevMaterials.7.124204

DO - 10.1103/PhysRevMaterials.7.124204

M3 - Article

VL - 7

JO - Physical Review Materials

JF - Physical Review Materials

SN - 2475-9953

IS - 12

M1 - 124204

ER -