Single-Precursor Intermediate Shelling Enables Bright, Narrow Line Width InAs/InZnP-Based QD Emitters
Laxmi Kishore Sagar, Golam Bappi, Andrew Johnston, Bin Chen, Petar Todorović́, Larissa Levina, Makhsud I. Saidaminov, F. Pelayo Garcı́a de Arquer, Sjoerd Hoogland, Edward H. Sargent
Abstract
Bright, narrow spectrum infrared emitters, particularly Cd- and Pb-free materials, are of interest for bioimaging, photodetection, and telecommunications. InAs-based quantum dots (QDs) are promising emitters in this spectral range; however, efforts to increase the photoluminescence quantum yield (PLQY) tend to broaden the PL line width as a consequence of interfacial defect formation when thick shells, lattice-mismatched with the core, are employed. Here we report that developing a single-precursor complex for InZnP growth enables uniform shell growth that maintains the excellent size dispersion (6%) of the cores. The introduction of this intermediate layer is key to facilitate the subsequent growth of different shells to improve radiative recombination without sacrificing size uniformity. The growth of InAs/InZnP/ZnSe leads to a PL full-width at half-maximum (fwhm) of 100 meV at 1.12 eV with a PLQY of 14%. We then further introduce an additional GaP layer to increase the radiative/nonradiative relative rate. InAs/InZnP/GaP/ZnSe QDs reach a PLQY of 23% while maintaining a narrow fwhm.