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

Abstract

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.