Two-wavelength Quantum Dot Mid-Infrared Photodetectors Using Solution Process Method

This novel report is a way to achieve a mid-infrared photodetector based on quantum dots, which is designed and simulated to be fabricated by the solution process method, which provides low cost and ease of fabrication. To design the proposed structure, the absorber layer is composed of two different sizes of quantum dots, in which, thanks to the intersubband transitions of carriers, two separate wavelengths of the mid-infrared spectrum are detected. Then, with the help of resonant tunneling effect, the excited carriers flow towards the interdigitated contacts and the output photocurrent is generated. For theoretical modeling, the Coupled rate equations and the Schrödinger-Poisson equations are calculated. Simulation results indicate that the peak responsivities are about 7.5(A/W) and 8(A/W), and the specific detectivities D* are about $5 \times 10^{11}$(cm.Hz
^1/2
W
^-1
) and $6 \times 10^{11}$(cm.Hz
^1/2
W
^-1
) for the wavelengths of $3 \mu \mathrm{m}$ and $5 \mu \mathrm{m}$, respectively.