• Volume 41,Issue 2,2022 Table of Contents
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    • >Infrared Physics, Materials and Devices
    • The band gap regulation of HgxCd1-xTe quantum dots by ion exchange and their near-infrared self-absorption characteristics

      2022, 41(2):377-383. DOI: 10.11972/j.issn.1001-9014.2022.02.001

      Abstract (362) HTML (416) PDF 2.15 M (2428) Comment (0) Favorites

      Abstract:In this paper, monodispersed CdTe quantum dots are synthesized by soft chemical method. Meanwhile, mercury cadmium telluride (HgxCd1-xTe) quantum dots with the quasi continuous visible to near-infrared spectrum are prepared by ion exchange adjusting the concentration of Hg2+. The variable temperature photoluminescence and self-absorption characteristics of near-infrared Hg0.33Cd0.67Te quantum dots are deeply analyzed. The results indicate that the fluorescence intensity of HgxCd1-xTe quantum dots decreases linearly with the increase of temperature (0~100 ℃). The spectral line broad and the peak position has a red-shift (12 nm). The partial overlap of absorption and emission spectra of quantum dots leads to self-absorption. The increase of self-absorption results in decrease of photoluminescence intensity while the concentration of quantum dots increases.

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    • Interfacial properties between Al2O3 and In0.74Al0.26As epitaxial layer on MIS capacitors

      2022, 41(2):384-388. DOI: 10.11972/j.issn.1001-9014.2022.02.002

      Abstract (245) HTML (164) PDF 2.24 M (1926) Comment (0) Favorites

      Abstract:Metal-Insulator-Semiconductor (MIS) capacitors were fabricated on In0.74Al0.26As/In0.74Ga0.26As/InxAl1-xAs heterostructure multilayer semiconductor materials. SiNx and SiNx/Al2O3 bilayer were applied as insulating layer to prepare MIS capacitors respectively. High-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) measurements indicated that, compared with SiNx deposited by inductively coupled plasma chemical vapor deposition (ICPCVD), Al2O3 deposited by atomic layer deposition (ALD) can effectively suppresses In2O3 at the interface between Al2O3 and In0.74Al0.26As. According to the capacitance-voltage (C-V) measurement result of MIS capacitors, the fast interface state density (Dit) of SiNx/Al2O3/In0.74Al0.26As was one order of magnitude lower than that of SiNx/In0.74Al0.26As. Therefore, it can be concluded that Al2O3 deposited by ALD as a passivation film can effectively reduce the interface state density between Al2O3 and In0.74Al0.26As, thereby reducing the dark current of p-In0.74Al0.26As/i-In0.76Ga0.24As/n-InxAl1-xAs photodiodes.

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