HgTe Quantum Dots for Near-, Mid-, and Long-Wavelength IR Devices

Mercury telluride colloidal quantum dots (CQD) hold potential for the fabrication of IR devices that operate in the range of near IR, through short-, mid-, and long wavelength (NIR, SWIR, MWIR, and LWIR, respectively). We synthesized a variety of colloidal HgTe QDs using the wet technique in a non-coordinating environment. Both a standard synthesis technique (mixing Hg and Te precursors and letting the nanocrystals grow and develop) and a more complex technique involving the controlled intermittent addition of precursors were applied. CQDs with sizes up to 20–30 nm were grown, although materials with sizes well above 10 nm did not show a distinct excitonic absorption peak. Our synthesized CQDs were used to fabricate photoconductive devices and measure their photoresponse. We present the synthesis techniques used in this work, photoconductive device fabrication and characterization. Devices with quantum efficiency of about 12.5% at a 4 V bias were obtained.