PbS and HgTe quantum dots for SW IR devices

HgTe and PbS colloidal quantum dots (CQD) with first excitonic absorption peak of about 2 μm and shorter (down to about 1 μm) have been synthesized and characterized. The synthesized CQDs were characterized using FTIR spectroscopy and TEM technique. The nanomaterials were tested for photo-electrical properties with photoconductive (PC) devices. The devices were fabricated by drop-casting a suspension of the CQDs on the fanout, followed by solid state ligand exchange (SSLE) process, and then spectral and electrical photoresponse of the device were measured. The SSLE process was evaluated thru absorption spectra of test samples. The device fabrication parameters were the number of deposited layers, the thickness of individual layers, the type of the substituting ligand, and the ligand exchange duration. For selected devices external quantum efficiency (EQE) was also determined.