In this article we report the development of 10×10 photodiode array by realizing heterojunction between mercury cadmium telluride (HgCdTe) quantum dot (diameter ~14 nm) and silicon responsive in mid wave infrared (MWIR) range (λ=3—5 μm) at room temperature. Performance of this optical sensor has been evaluated experimentally and Detectivity of 1.6×10⁸ cm Hz /W has been achieved at spectral wavelength of 3.5 μm at 300 K. This work ascertains the compatibility of chemically synthesized HgCdTe quantum dots with commercially available direct injection type readout integrated circuits (ROIC) for the development of low cost large format MWIR focal plane array (FPA).