Colloidal II–VI—Epitaxial III–V heterostructure: A strategy to expand InGaAs spectral response

For short wave infrared (SWIR) sensing, InGaAs is the leading technology combining high carrier mobility, high homogeneity, and complete control over the n-to-p doping. In the meanwhile, numerous alternative materials have tried to compete with InGaAs. Among them, colloidal nanocrystals with narrow bandgap can address the current issue in designing cost-effective sensors for the SWIR range. Rather than putting these two materials against each other, we design here a synergistic duo in which HgTe nanocrystals are used to broaden the spectral range of InGaAs while lifting the lattice matching constraints. We propose a diode geometry where a p-type HgTe NC array is coupled with n-type InGaAs wires, which are used as high mobility (μ > 1000 cm2 V−1 s−1) minority carrier extractors. This approach also demonstrates that Van der Waals heterostructures are not limited to graphene-like materials, and that bulk-like III–V semiconductors can also be light sensitized by colloidal nanoparticles. This work paves the way toward further synergies between epitaxially grown and colloidally grown semiconductors for infrared detection.