Publication date: 15th December 2025
The ligands of indium phosphide (InP) quantum dots (QDs) were polymerized by energetic Ar ions generated by plasma, and the polymerized ligands enabled the formation of 3-μm patterns through photolithography. In the first step, the ligand capping the QDs was oleic acid (OA), and changes in the OA ligands with plasma bias voltage, source power, and time were monitored using Fourier transform infrared (FT-IR) spectroscopy. The energy range for OA polymerization was then determined by analyzing changes in the 3006 cm⁻¹ peak. In the second step, photoresist (PR) was coated on the cross-linked QD film, and a PR pattern was formed using conventional i-line UV lithography. Finally, the unmasked QD region is selectively removed by Ar sputter etching in plasma under optimized conditions of 150 W source power and 300 V bias voltage, forming a 3-μm scale QD pattern. This study utilized plasma-induced cross-linking to induce polymerization of QD ligands, ensuring compatibility with photolithography processes.
