Surface Passivation of HgTe Nanocrystals Enabling E <sub>G</sub> /2 Open‐Circuit Voltage and Their Coupling to Dielectric Cavity for Narrow Detection
Abstract
ABSTRACT Colloidal HgTe nanocrystals (NCs) offer a versatile, solution‐processable platform for infrared optoelectronics, yet their integration into high‐performance diodes has long been hindered by surface‐trap‐limited open‐circuit voltage ( V OC ), high dark currents, and insufficient thermal robustness. Here, we demonstrate that ultrathin CdS shells grown around HgTe cores, combined with an optimized cation‐exchange protocol, enable unprecedented passivation of trap states while reducing species interdiffusion and simultaneously improving interfacial band alignment. Implemented in a diode architecture employing SnO 2 electron‐transport layers and Ag‐doped CdTe hole‐selective contacts, these HgTe/CdS NCs yield a two orders of magnitude reduction in dark current and a V OC of 420 mV; exceeding half the optical bandgap for the first time in HgTe‐based NC photodiodes. Operated at room temperature, the devices exhibit detectivities up to 1.5 × 10 1 1 Jones and fast response times below 200 ns. Leveraging the reduced dark current and improved film homogeneity, we further integrate the photodiodes into a dielectric Bragg cavity to achieve ultranarrow detection linewidths down to 90 cm −1 at 1.55 µm. This diode design benefits from a strong field enhancement, while the device absorption limits the linewidth. Our results establish surface‐passivated HgTe NCs as a viable route toward compact, narrowband, and thermally stable infrared photodetectors.
Article Details
Authors (18)
Albin Colle
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,
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,
Jiho Roh
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,
Tommaso Gemo
Sorbonne Université, CNRS, Institut des NanoSciences de Paris 1 , 4 place Jussieu, 75005 Paris,
Diogo Almeida
Institut des NanoSciences de Paris CNRS Sorbonne Université Paris France
Adrien Khalili
Sorbonne Université, CNRS, Institut des NanoSciences de Paris 1 , 4 place Jussieu, 75005 Paris,
Yoann Prado
Sorbonne Université, CNRS, Institut des NanoSciences de Paris 1 , 4 place Jussieu, 75005 Paris,
Xavier Lafosse
Centre de Nanosciences et de Nanotechnologies CNRS Université Paris‐Saclay Palaiseau France
Sandrine Ithurria
Laboratoire de Physique et d'Etude des Matériaux, ESPCI, PSL Research University, Sorbonne Université, CNRS 4 , 10 rue Vauquelin, 75005 Paris,
Mathieu G. Silly
Synchrotron SOLEIL L’Orme des Merisiers, Saint Aubin Gif sur Yvette 91192 France
Pavel Dudin
Synchrotron SOLEIL L'Orme des Merisiers Saint‐Aubin France
James K. Utterback
Institut des NanoSciences de Paris CNRS Sorbonne Université Paris France
José Avila
Synchrotron SOLEIL L'Orme des Merisiers Saint‐Aubin France
Debora Pierucci
Sorbonne Université, CNRS, Institut des NanoSciences de Paris 1 , 4 place Jussieu, 75005 Paris,
Emmanuel Lhuillier