Abstract
Separation of epitaxial thin films on a growth substrate and transfer onto other materials for functional heterostructures have boosted the transformative impact on science and technology. However, this scheme has proved challenging in thin-film thermoelectrics but promises a vast range of applications beyond the limited device configurations of bulk thermoelectrics. Here, the high-quality Bi0.5Sb1.5Te3 (BST) epitaxial thin film on a sapphire substrate grown by spontaneous van der Waals epitaxy (vdWE) is exfoliated and transferred onto versatile materials, creating high-performance thermoelectric membranes. Unprecedented millimeter-size vdWE BST membranes are produced by etching a pseudomorphic Te monolayer on the surface of a sapphire substrate in dilute HF solution. The intact exfoliation and direct transfer for vdWE BST membranes maintain the high-quality crystallinity, resulting in the remarkable zT value (∼0.9 at 300 K). These results represent the realization of long-pursued but undemonstrated high-performance thin-film thermoelectrics, paving the way for the design and fabrication of arbitrarily shaped thermoelectric devices.
Original language | English |
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Pages (from-to) | 2378-2385 |
Number of pages | 8 |
Journal | ACS Energy Letters |
Volume | 6 |
Issue number | 7 |
DOIs | |
State | Published - 9 Jul 2021 |