High-detectivity InAs quantum-dot infrared photodetectors grown on InP by metal–organic chemical–vapor deposition

We report a high-detectivity InAs quantum-dot infrared photodetector. The InAs quantum dots were grown by self-assembly on InP substrates via low-pressure metal–organic chemical–vapor deposition. Highly uniform quantum dots with a density of $4\times {10}^{10}{\mathrm{cm}}^2$ were grown on a $\mathrm{GaAs}∕\mathrm{InP}$ matrix. Photoresponse was observed at temperatures up to 160 K with a peak of $6.4\mu \mathrm{m}$ and cutoff of $6.6\mu \mathrm{m}$ . Very low dark currents and noise currents were obtained by inserting ${\mathrm{Al}}_{0.48}{\mathrm{In}}_{0.52}\mathrm{As}$ current blocking layers. The background-limited performance temperature was 100 K. A detectivity of $1.0\times {10}^{10}\mathrm{cm}{\mathrm{Hz}}^{1∕2}∕\mathrm{W}$ was obtained at 77 K with a bias of $-1.1\mathrm{V}$ .