Synthesis of HgTe QDs in the 1000-2500nm spectral range

HgTe is semi-metallic as a bulk material but when the crystal dimensions are reduced to the nanometer range, a band gap or HOMO-LUMO gap that is tunable throughout the IR region by the nanocrystal size opens up. The IR contains a number of technologically important wavelength ranges such as the 1300-1600 nm window used for telecommunication and the mid IR used for infrared spectroscopy. For these applications, HgTe quantum dots could be used for the emission, detection or modulation of light. In this study, we discuss a novel synthesis for HgTe QDs. Using XRD and TEM, we show that the synthesis results in HgTe nanocrystals with the zincblende crystal structure and diameters of a few nanometer. Moreover, the HgTe QDs exhibit a clear absorption onset and a narrow photoluminescence spectrum corresponding to the quantum confined band gap transition. A detailed study of the reaction yield and the nanocrystal size as a function of time provides the insight in the reaction mechanism needed to tune the nanocrystal size and, concomitantly, the wavelength of absorption onset and photoluminescence. As a result, HgTe QDs with a spectrally narrow emission in the 1000 to 2500 nm range could be obtained. Our findings thus provide a thorough understanding of the mechanism of HgTe QD synthesis and result in materials that can be readily explored for applications such as photo detection and IR light emission.HgTe is semi-metallic as a bulk material but when the crystal dimensions are reduced to the nanometer range, a band gap or HOMO-LUMO gap that is tunable throughout the IR region by the nanocrystal size opens up. The IR contains a number of technologically important wavelength ranges such as the 1300-1600 nm window used for telecommunication and the mid IR used for infrared spectroscopy. For these applications, HgTe quantum dots could be used for the emission, detection or modulation of light. In this study, we discuss a novel synthesis for HgTe QDs. Using XRD and TEM, we show that the synthesis results in HgTe nanocrystals with the zincblende crystal structure and diameters of a few nanometer. Moreover, the HgTe QDs exhibit a clear absorption onset and a narrow photoluminescence spectrum corresponding to the quantum confined band gap transition. A detailed study of the reaction yield and the nanocrystal size as a function of time provides the insight in the reaction mechanism needed to tune the nanocrystal size and, concomitantly, the wavelength of absorption onset and photoluminescence. As a result, HgTe QDs with a spectrally narrow emission in the 1000 to 2500 nm range could be obtained. Our findings thus provide a thorough understanding of the mechanism of HgTe QD synthesis and result in materials that can be readily explored for applications such as photo detection and IR light emission.C