Controlling the doping density of the quantum dot solid and engineering the device structure require an extremely sophisticated technique, which hinders consistent doping density and restricts further development in understanding the fundamental photophysics and manufacturing process. Here, we report an air-stable and highly reproducible MWIR CQDs photodiode by incorporating synthesized p-doped Ag-HgTe colloidal nanocrystals (NCs). The Ag-HgTe alloy NCs allow clearly defined p-doped QDs layers, leading to uniform dopant distribution and the ease of engineering device fabrication. By optimizing the doping density, we achieved an average noise equivalent temperature difference of below 10 mK at 78 K with the self-powered MWIR photodiode sensor.