In this paper, we propose new detectivity enhanced infrared detectors in which metamaterial cells are used to harvest the IR energy. Analytical models are developed and numerically verified to predict the behavior of the proposed detectors. Detectivity improvement factor (DIF) is defined to compare the performance of the proposed detectors with traditional ones. Numerical results show that the proposed detectors can provide a DIF value as high as 60. A comprehensive parametric study is performed to investigate how different physical and electrical parameters affect the performance of the proposed detectors. In this study, the effects of the shape of the resonators, their dimensions, and the metal from which they are made, on the performance of the proposed detectors, are investigated.