Defect-Mediated Growth of Layered Lateral Bi2Te3-Sb2Te3-Bi2Te3 Heterostructures

Goyal, N and Jagadish, K and Ravishankar, N (2024) Defect-Mediated Growth of Layered Lateral Bi2Te3-Sb2Te3-Bi2Te3 Heterostructures. In: Journal of Physical Chemistry C .

PDF jou_phy_che_128_18_2024.pdf - Published Version Restricted to Registered users only Download (3MB)

Abstract

In-plane heterostructures of Bi2Te3-Sb2Te3 (BT-ST) have garnered significant interest owing to their topological properties and their applications as thermoelectric materials and in p-n junction devices. While various solution-based approaches have been employed in the past for heterostructure formation, using multistep methods, achieving one-step synthesis has been challenging. Herein, a successful synthesis of BT-ST heterostructure using a one-pot solution-based synthetic strategy is reported, where in situ generated Bi2Te3 nanosheet acts as a template to grow Sb2Te3. Furthermore, this strategy has been extended to form the double shell heterostructure of Bi2Te3-Sb2Te3-Bi2Te3 (BT-ST-BT). Control experiments by varying precursor ratio, time, and temperature have been conducted to elucidate the growth process. Cross-section high-angle annular dark field scanning-transmission electron microscope imaging reveals the existence of steps on the growth surface, providing clues to a screw-dislocation-mediated growth mechanism. To gain insights into the screw-dislocation-driven growth, atomic-resolution imaging has been carried out by using an aberration-corrected scanning-transmission electron microscope. The presence of screw dislocations is evident from the 2-layer defect at the interface, owing to which the usual quintuple-layer structure is perturbed by the formation of a 5-layer 7-layer structure. These dislocations contain Te-Bi/Sb layers and join the upper block of one-quintuple layer (Te-Bi/Sb) to the lower block of other quintuple layers (Bi/Sb-Te) via atom inversion and serve as attachment sites for further growth of Bi2Te3 onto the BT-ST heterostructure. The screw dislocations are found to originate from pristine Bi2Te3 and play a critical role in the overall growth process. Overall, this study demonstrates the versatility of a solution-based approach in designing multishell nanostructures and detailed analysis of interfaces, which provide insights into the atomic arrangement during the screw-dislocation-mediated growth mechanism. © 2024 American Chemical Society

Item Type:	Journal Article
Publication:	Journal of Physical Chemistry C
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to American Chemical Society.
Keywords:	Antimony compounds; Atoms; Bismuth; Bismuth compounds; Screw dislocations; Screws; Tellurium compounds; Thermoelectricity; Topology, Growth mechanisms; Growth process; Junction devices; Layer structures; Multi step methods; P-n junction; Solution based approaches; Thermo-Electric materials; Thermoelectric material; Topological properties, Transmission electron microscopy
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	24 May 2024 05:16
Last Modified:	24 May 2024 05:16
URI:	https://eprints.iisc.ac.in/id/eprint/85048

Actions (login required)

View Item