Growth of High-Quality Tellurium Thin Films via Substrate Engineering for High-Performance p-Type Field-Effect Transistors and Circuits

Project: Research

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With the miniaturization of traditional silicon-based field-effect transistors (FETs) approaching its physical limitation, the burgeoning development of two-dimensional (2D) semiconductors provides a promising strategy to solve this challenge. The absence of surface dangling bonds endows 2D materials with the superiority in building new architectures different from the classical von Neumann architecture and highly-integrated low-power-consumption circuits. Nowadays, various 2D materials have been already developed for fabrication of high-performance n-type FETs and circuits. However, the lack of stable high-quality p-type 2D semiconductors has become the major bottleneck for the fabrication of p-type FETs with large current on/off ratio, high hole mobility, and small subthreshold swing (SS) and even more complex low-power-consumption complementary metal-oxide-semiconductor (CMOS) circuits. This project aims to tackle this bottleneck by growth of high-quality tellurium (Te) thin films through substrate engineering in a chemical vapor deposition (CVD) system. The PI has rich experience on the growth/characterization of 2D semiconductors and the design/fabrication of nanoelectronics, including transistors and logic circuits, based on various 2D materials (especially Te and SexTe1-xalloys). The previously reported low-temperature evaporated polycrystalline Te thin films possess rich defects and grain boundaries which heavily limit the subsequent device performance. In this project, we aim to grow high-quality Te thin films through substrate engineering in the CVD growth, and then use them as channel materials to construct high-performance p-type FETs and circuits.Ourpreliminary resultsalready show that Te nanoflakes grown on the atomically flat hexagonal boron nitride (h-BN) surface by a CVD method exhibit record-high hole mobilities (> 1000 cm2V-1s-1). High-quality Te thin films will be grown on substrates with single crystal facet-exposed surfaces (e.g. sapphire) and the obtained Te thin films will be used for the fabrication of transistors, logic gates and circuits. The successful accomplishment of this project will deliver Te-based p-type FETs with figure of merits that are superior to that of the currently reported p-type FETs based on other 2D materials (e.g. black phosphorus and WSe2) and Te grown by other methods. Specifically, the Te p-type FETs are expected to achieve a respectable hole mobility (> 1000 cm2V-1s-1), high current on/off ratio (> 104), and small SS (< 80 mV dec-1). A p-type metal-oxide-semiconductor (p-MOS) circuit based on hundreds of Te FETs will be also demonstrated. Such novel p-type transistors could find their applications in highly integrated 2D material-based logic circuits and flexible nanoelectronics, and could promote the rapid development of 2D material-based nanoelectronics. 


Project number9043304
Grant typeGRF
StatusNot started
Effective start/end date1/01/23 → …