Project Details
Projekt
Rare-earth nitride based heterostructures for integrated thermoelectrics
Applicants
Dr. Van Duc Dinh, Ph.D.; Professor Dr. Gregor Koblmüller; Privatdozent Dr. Markus R. Wagner
Subject Area
Synthesis and Properties of Functional Materials
Term
since 2025
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 563156864
This proposal aims to establish novel rare-earth transition-metal (TM) nitrides and mixed TM/group-IIIa nitrides as a promising class of high-temperature thermoelectric materials for integrated nitride-device technologies. Based on the applicants' recent advances in the areas of thin-film TM-nitride growth and thermoelectric transport characterization, the focus of this project is to explore the narrow-gap TM-nitrides (ScN, CrN) and mixed allotropes with isoelectronic group-IIIa elements, given their significant potential in high-temperature thermoelectric applications. Particular attention will be paid to creating phonon-glass/electron-crystal-like compounds by controlling disorder effects, alloying, and developing advanced heterostructures using ultrahigh-purity molecular beam epitaxy methods, thereby tailoring the key thermoelectric parameters, such as electrical and thermal conductivity, and thermoelectric power factor over large temperature ranges. Three connected approaches will be pursued that logically build upon each other in forming complex TM-nitride thermoelectrics with enhanced performance: (i) the investigation of binary rocksalt thin films (ScN, CrN) and the tunability of lattice disorder through the introduction of defects (e.g., vacancies and other point defects) and substitutional doping. (ii) The development of mixed-TM/group-IIIa nitride alloys within and beyond the spinodal decomposition limit and the phase-mismatch-induced formation of nanocomposite structures, to tune thermoelectric properties towards the alloy limit. (iii) The exploration of two-dimensional quantum-well (superlattice) heterostructures to exploit beneficial quantum confinement and energy filtering concepts in enhancing thermopower, while suppressing thermal conductivity through phonon scattering at artificial interfaces. Thereby, this project meets the central vision of this SPP-initiative, as our research opens new functionalities of novel nitrides and further enables monolithically integrated concepts in active heat management and power conversion of nitride-based devices, which will be pursued in the second phase of this program.
DFG Programme
Priority Programmes
International Connection
China, Finland, USA
Co-Investigators
Dr. Christian Carbogno; Professor Dr. Martin Feneberg; Professor Dr. Michael Lehmann; Professor Dr. Christian Thomsen
Cooperation Partners
Lucas Lindsay, Ph.D.; Privatdozent Dr. Ilja Makkonen; Professor Bo Sun, Ph.D.
