Temperature-induced absolute energy shift of the electronic spectrum in HgTe nanocrystals
Abstract
Mercury telluride (HgTe) nanocrystals (NCs) are promising materials for infrared photodetection due to their size-tunable band edges and compatibility with colloidal synthesis. While optical studies have established the temperature dependence of their relative bandgaps, the evolution of their absolute electronic spectrum with cooling remains poorly understood, despite its critical role in the device operation. In this work, we investigate in situ the temperature-induced absolute energy shift of HgTe NCs' electronic states with varying band edge energies, using X-ray photoemission spectroscopy. We observe a systematic and reversible rigid shift of core levels toward lower binding energies upon cooling, reaching approximately 80 meV per 100 K, four times larger than the corresponding optical band edge shift (≈20 meV). This behavior is consistent across different NC sizes, making the impact more dramatic for the narrower bandgap NCs. Such absolute energy shifts can significantly alter carrier densities and interfacial band alignments, potentially creating Schottky barriers and reducing extraction efficiency in photodiode architectures. Our findings highlight the necessity of accounting for temperature-induced absolute energy shifts in the design of next-generation HgTe NC-based infrared detectors.
Article Details
Journal Info
Applied Physics Letters
American Institute of Physics
Authors (17)
Tommaso Gemo
Sorbonne Université, CNRS, Institut des NanoSciences de Paris 1 , 4 place Jussieu, 75005 Paris,
Dario Mastrippolito
Sorbonne Université, CNRS, Institut des NanoSciences de Paris 1 , 4 place Jussieu, 75005 Paris,
Mariarosa Cavallo
Sorbonne Université, CNRS, Institut des NanoSciences de Paris 1 , 4 place Jussieu, 75005 Paris,
Giorgia Strobbia
Sorbonne Université, CNRS, Institut des NanoSciences de Paris 1 , 4 place Jussieu, 75005 Paris,
Albin Colle
Sorbonne Université, CNRS, Institut des NanoSciences de Paris 1 , 4 place Jussieu, 75005 Paris,
Marco Paye
Sorbonne Université, CNRS, Institut des NanoSciences de Paris 1 , 4 place Jussieu, 75005 Paris,
Jiho Roh
Sorbonne Université, CNRS, Institut des NanoSciences de Paris 1 , 4 place Jussieu, 75005 Paris,
Adrien Khalili
Sorbonne Université, CNRS, Institut des NanoSciences de Paris 1 , 4 place Jussieu, 75005 Paris,
Clement Gureghian
Sorbonne Université, CNRS, Institut des NanoSciences de Paris 1 , 4 place Jussieu, 75005 Paris,
Erwan Bossavit
Sandrine Ithurria
Laboratoire de Physique et d'Etude des Matériaux, ESPCI, PSL Research University, Sorbonne Université, CNRS 4 , 10 rue Vauquelin, 75005 Paris,
Yoann Prado
Sorbonne Université, CNRS, Institut des NanoSciences de Paris 1 , 4 place Jussieu, 75005 Paris,
Sébastien Sauvage
Centre de Nanosciences et de Nanotechnologies, CNRS, Université Paris-Saclay 5 , 91120 Palaiseau,
Mathieu G. Silly
Synchrotron SOLEIL L’Orme des Merisiers, Saint Aubin Gif sur Yvette 91192 France
Nicolas Péré-Laperne
LYNRED, Actipole—CS 10021 2 , 364 route de Valence, 38113 Veurey-Voroize,
Debora Pierucci
Sorbonne Université, CNRS, Institut des NanoSciences de Paris 1 , 4 place Jussieu, 75005 Paris,
Emmanuel Lhuillier