High detectivity InGaAs/InGaP quantum-dot infrared photodetectors grown by low pressure metalorganic chemical vapor deposition

We report a high detectivity middle-wavelength infrared quantum dot infrared photodetector (QDIP). The InGaAs quantum dots were grown by self-assembly on an InGaP matrix via low pressure metalorganic chemical vapor deposition. Photoresponse was observed at temperatures above 200 K with a peak wavelength of 4.7 μm and cutoff wavelength of 5.2 μm. The background limited performance temperature was 140 K, and this was attributed to the super low dark current observed in this QDIP. A detectivity of ${\text{3.6×10}}^{10}\hspace{0.5em}{\mathrm{cm Hz}}^{\text{1/2}}/\mathrm{W},$ which is comparable to the state-of-the-art quantum well infrared photodetectors in a similar wavelength range, was obtained for this InGaAs/InGaP QDIP at both $\text{T=77\hspace{0.5em}}\mathrm{K}$ and $\text{T=95\hspace{0.5em}}\mathrm{K}$ at biases of −1.6 and −1.4 V, respectively.