Furthermore, it is likely that the temperature-dependent responsivity can be improved by employing different ligands, and optimized QD/ligand combinations may raise the operational temperature improving the specific detectivity. For example, a solution-based ligand exchange with a combination of organic and inorganic ligands (2-mercaptoethanol, HgCl2), followed by QD deposition leads to HgTe QD films with higher charge carrier mobilities. The latter leads to longer charge carrier diffusion-length which is beneficial for the extraction of photoinduced charge carriers out of thicker QD films and likely results in an improved device operational speed. The conduction-and valence band positions can be modified by varying the amounts of HgCl2 in the ligand exchange procedure, and can lead to an optimized band alignment with graphene.