Terahertz detection with tunneling quantum dot intersublevel photodetector

The characteristics of a tunnel quantum dot intersublevel photodetector, designed for the absorption of terahertz radiation, are described. The absorption region consists of self-organized ${\mathrm{In}}_{0.6}{\mathrm{Al}}_{0.4}\mathrm{As}∕\mathrm{Ga}\mathrm{As}$ quantum dots with tailored electronic properties. Devices exhibit spectral response from $20\text{to}75\mu \mathrm{m}$ $(\sim 4\mathrm{THz})$ with peak at $\sim 50\mu \mathrm{m}$ . The peak responsivity and specific detectivity of the device are $0.45\mathrm{A}∕\mathrm{W}$ and ${10}^8\mathrm{cm}{\mathrm{Hz}}^{1∕2}∕\mathrm{W}$ , respectively, at $4.6\mathrm{K}$ for an applied bias of $1\mathrm{V}$ . Response to terahertz radiation is observed up to $150\mathrm{K}$ .