BiCuTeO Thin Films: Thermoelectric Properties and Photodetection Applications at Hebei University

Release time：

2025-11-07

The layered p-type semiconductor BiCuTeO exhibits intrinsically low thermal conductivity and exceptional electrical transport properties, making it a promising high-performance thermoelectric material for the mid-temperature range.All previously reported BiCuTeO bulk materials possess a tetragonal crystal structure with space group P4/nmm. Recently, Professor Shufang Wang's team at Hebei University synthesized single-phase oriented BiCuTeO thin films on lanthanum aluminate substrates via pulsed laser deposition. They discovered a hexagonal crystal structure differing from the bulk phase, consisting of [Bi₂O₂]²⁺ and [Cu₂Te₂]²⁻ layers alternately stacked along the c-axis, with lattice parameters of c = 12.45 Å and a = b = 4.3 Å.Electrical transport measurements revealed that the hexagonal BiCuTeO thin films exhibit metallic conduction behavior within the 300-600 K temperature range, achieving a thermoelectric power factor (PF) of 7.7 μW cm⁻¹ K⁻² at 600 K.Phonon spectrum and electronic band structure calculations further theoretically confirmed the thermodynamic and dynamic stability of this hexagonal phase.These findings have been published in Applied Physics Letters 126, 233905 (2025) under the title "A hexagonal phase of BiCuTeO films: Growth, crystal structure, and thermoelectric properties".

The hexagonal BiCuTeO thin film exhibits high anisotropy in both electrical conductivity and Seebeck coefficient, making it a promising candidate for constructing transverse thermoelectric devices.Building on this, the authors fabricated BiCuTeO thin films with 10° c-axis tilt and synergistically modulated the detection sensitivity and temporal responsivity of transverse thermoelectric devices through Ag doping and composite effects.Experimental results show that under 308 nm pulsed laser irradiation, the detector yields an open-circuit voltage output with a high sensitivity of 20 V/mJ without any external bias, featuring rise and decay times of 52 ns and 195 ns, respectively. This demonstrates the significant application prospects of hexagonal BiCuTeO thin films in self-powered, highly sensitive, and fast-response photodetectors.These results have been published in Applied Physics Letters 127, 063501 (2025) under the title "High-performance pulsed light detector based on the transverse thermoelectric effect of the c-axis inclined BiCuTeO:Agₓ films".

This work was supported by the National Natural Science Foundation of China and the Central Government Guides Local Science and Technology Development Fund.

Research Team Introduction

Guoying Yan, Associate Professor and Master's Supervisor at the School of Physics, Hebei University.Her research focuses on transverse thermoelectric effects in thin films for photodetector and thermal detector applications. Recently, as first/corresponding author, she has published over 10 SCI papers in journals including Nano Energy and Applied Physics Letters, with 9 authorized Chinese invention patents including 2 commercialized.

Shufang Wang, Distinguished "Kunyu Scholar" Professor, Doctoral Supervisor, and Principal Investigator of the Energy Conversion Materials and Devices Group at Hebei University.Shufang Wang has long been engaged in the design of semiconductor thermoelectric/optoelectronic materials, regulation of physical properties, and device applications. Recently, as corresponding author, she has published over 100 SCI papers in journals including Nature Commun., Adv. Mater., Sci. Bull., Phys. Rev. B, and Appl. Phys. Lett.. She also holds positions including Council Member of the Chinese Optical Society, Standing Committee Member of its Optoelectronic Technology Committee, and Board Member of the Thermoelectric Materials & Applications Branch of the Chinese Materials Research Society.