Tellurium-based materials for nanoelectronics: applications, challenges, and outlooks

The realization of high-performance P-type semiconductors remains a central challenge in oxide semiconductors due to the strong localization of holes within oxygen 2p-derived valence bands. This orbital limitation hampers the development of efficient hole conduction pathways, resulting in low hole mobility and poor device characteristics, contrary to the success of N-type oxides such as indium gallium zinc oxide (IGZO) and ZnO. Recently, tellurium-based oxides have emerged as promising candidates to overcome these barriers, offering intrinsic p-type behavior, tunable band structures, and compatibility with low-temperature, back-end-of-line processes. Their unique crystal structures, ranging from helical-chain-derived hexagonal phases based on Te to tetragonal-phase TeOx, enable anisotropic charge transport, reduced non-radiative recombination, and low Schottky barrier heights facilitating efficient hole injection. These advantages have been successfully exploited in P-type field-effect transistors, broadband photodetectors, and multifunctional sensors thanks to the broad spectral absorption, strong electromechanical coupling, and environmental stability of TeOx. This review highlights the material properties of tellurium-based oxides, their device-level performance, challenges, and outlooks for their integration into next-generation nanoelectronic and optoelectronic systems.