Synthesis and Surface Engineering of Indium Antimonide Quantum Dots for IR Photodetectors

Synthesis and Surface Engineering of Indium Antimonide Quantum Dots for IR PhotodetectorsYongju Kwon a, Marcus Scheele aa Institut für Physikalische und Theoretische Chemie, Universität Tübingen, 72076 Tübingen, GermanyMaterials for Sustainable Development Conference (MATSUS)Proceedings of MATSUS Spring 2024 Conference (MATSUS24)#NextGenPD - Next Generation Photo-and-radiation detectorsBarcelona, Spain, 2024 March 4th - 8thOrganizers: Ardalan Armin and Nicola GaspariniOral, Yongju Kwon, presentation 126DOI: https://doi.org/10.29363/nanoge.matsus.2024.126Publication date: 18th December 2023 Colloidal infrared (IR) quantum dots (QDs) have been studied with many advantages, such as tunable absorption and fluorescence emission spectra, high molar extinction coefficients, high photoluminescence (PL) quantum yield, high stability, cost-efficient and scalable synthesis, and solution processability. Most of the reported IR-active QDs are based on materials containing toxic heavy metals, such as PbS and HgTe QDs. III- V semiconductors containing one group-13 and one group-15 element of the periodic table are highly promising Pb- and Hg-free alternative materials.[1] Colloidal InSb QDs have been considered as a low-toxic alternative to Pb or Hg chalcogenide QDs. The InSb has a large excitonic Bohr radius of ~60 nm, and it allows the band gap of InSb QDs to be widely tuned in the IR spectral range through size control. However, only a few chemical synthesis methods have been reported due to the limited precursors and the synthesized InSb QDs have featureless or broad excitonic absorption peaks showing extremely broad size distribution so far. Here, we report the chemical synthesis and surface engineering of colloidal InSb QDs. In the synthesis part, various synthesis parameters such as precursors, temperature, time, and an introduction of additional ions are explored to produce InSb QDs with unprecedented optical quality. The optical properties of InSb QDs are studied mainly based on the wavelength and the width of the excitonic absorption features. We demonstrate full tunability of the first excitonic absorption peak in the IR range from 700 to 2000 nm and narrow line widths by virtue of an improved size homogeneity of the InSb QDs. The effect of each synthesis parameter on the optical properties of InSb QDs and their growth mechanism will be discussed. In the surface engineering part, the surface ligands of InSb QDs are altered from the original long-chain organic ligands to short-chain ligands to afford conductive InSb QDs films. Several ligands were tested and their optical/structural properties of InSb QDs were compared before and after surface modification. With the thus optimized experimental conditions, we obtain InSb QDs films with high stability, high conductivity, and suitable band energy levels for application as environmentally benign IR photodetectors. References:[1] Yongju, K.; Juwon, O.; Eunjae, L.; Sang, H, L.; Anastasia, A.; Gyuhyun, B.; Jeongmin, K.; Dongho, K.; Sungjee, K, Evolution from unimolecular to colloidal-quantum-dot-like character in chlorine or zinc incorporated InP magic size clusters. Nature Communications 2020, 11, 3127.© FUNDACIO DE LA COMUNITAT VALENCIANA SCITOnanoGe is a prestigious brand of successful science conferences that are developed along the year in different areas of the world since 2009. 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