Synthesis of blue-to-green emitting $In_{1-x}Ga_{x}P$-based quantum dots through $Ga^{3+}$ composition control

Abstract

InP quantum dot (QD) has a bulk band gap (at 300 K) at 1.35 eV. They are widely used in the display field as eco-friendly QDs with emission wavelengths in the visible light region. However, unlike red-emitting Cd-free QD that shows highly efficient optical properties, there are several problems to be solved for blue and green emission. Especially, in terms of thermodynamics, it is hard to implement blue-emitting InP based QDs due to size limitations. Therefore, this paper introduces a gallium phosphide (GaP) semiconductor with a larger band gap than indium phosphide (InP) to form an alloy structure, thereby synthesizing alloy core capable of controlling gallium composition. This was analyzed through X-ray diffraction (XRD) analysis and inductively coupled plasma spectroscopy analysis. In addition, InGaP based heterostructure QDs with blue-to-green emission tunability were synthesized through zinc chalcogenide shell stacking, and applicability in the display field was confirmed through blue light absorption (at 450 nm) test and photo stability test for In1-xGaxP based QD.