Analytical Modeling for Photocurrent and Detectivity of TiO2/ZnS Core-Shell Quantum Dot Photodetectors

In this paper, a theoretical model has been presented to calculate the photocurrent and detectivity in a TiO2/ZnS core-shell quantum dot (CSQD) photodetector. Analytical modeling permits to calculate the available photocurrent and corresponding detectivity from the CSQD structures. In this theoretical model, the subband energy levels of the CSQD are estimated using the 3D symmetric quantum box structures with a finite potential barrier. The finite band offset determines the number of available subband energy levels in the CSQD structures depending on the size of the core. Theoretical results show the variation of photocurrent and corresponding detectivity with different core sizes of the CSQD for a constant shell thickness. The calculations indicate that for electronic intersubband transitions detectivity is higher compared with the hole transitions.