Seeded Growth of HgTe Nanocrystals for Shape Control and Their Use in Narrow Infrared Electroluminescence

摘要

HgTe colloidal nanocrystals (NCs) have become a promising building block for infrared optoelectronics. Despite their cubic zinc blende lattice, HgTe NCs tend to grow in a multipodic fashion, leading to poor shape and size control. Strategies to obtain HgTe NCs with well-controlled sizes and shapes remain limited and sometimes challenging to handle, increasing the need for a new growth process. Here, we explore a synthetic route via seeded growth. In this approach, small HgTe seeds are nucleated in a first step, and they show narrow and bright photoluminescence with 75 quantum yield in the near infrared region. Once integrated into light emitting diodes, these seeds lead to devices with high radiance up to 20 W·Sr~(–1)·m~(–2) and a long lifetime. Heating HgTe seeds formed at the early stage promotes the formation of sphere-shaped HgTe with tunable band edges from 2 to 4 μm. Finally, the electronic transport tests conducted on sphere-shaped HgTe NC arrays reveal enhanced mobility and stronger temperature dependence compared to the multipodic shaped particles.