Abstract
This paper reports the results on fabrication methodology and photoresponse characteristics of Mg2Si0.53Ge0.47 pn-junction photodiode. At first, we have grown a Mg2Si0.53Ge0.47 single crystal with the Vertical Bridgman growth process. The grown crystal was characterized structurally and electrically by XRD, Laue, and Hall Effect measurements. XRD revealed the single-phase composition, Mg2Si0.53Ge0.47, of the grown crystal ingot. The clear Laue symmetrical diffraction pattern showed the single crystalline nature of the grown crystal. The Hall Effect measurement revealed the n-type conduction and the moderate Hall mobility (258 cm2/Vs), electrical resistivity (6.03E-02 Ω. cm), and carrier density (4.02E+17 cm-3) of the grown crystal. Such carrier density is low enough to allow depletion region formation in case of pn-junction diodes. In that sense, we have made up for the first time Mg2Si0.53Ge0.47 pn-junction photodiode by thermal diffusion of a thin Ag layer into n-Mg2Si0.53Ge0.47 substrate. The fabricated diode had an obvious rectification behavior and demonstrated a clear zero-biased photoresponse in the wavelength range from 0.95 to 1.85 μm, indicating its prominence for IR sensation in that wavelength domain.
Highlights
INTRODUCTIONMg2Si and its alloys with Mg2Sn and Mg2Ge have attracted increasing area of interest for thermoelectric and optoelectronic applications due to affordability, nontoxicity and crustal abundance of their constituents.[1,2,3] In addition, these materials have a high absorption coefficient near their absorption edge and narrow energy band gap values in the range from 0.3 to 0.7 eV.[4,5,6,7,8] In that sense, they could be implemented as a secure option to the current toxic Hg-based IR sensors for night vision applications and short-wavelength IR light detection
Our results indicated the significance of Mg2Si0.53Ge0.47 crystal as a potential candidate for IR sensation and night vision applications
Using the software Fullprof, the lattice constant of Mg2Si0.53Ge0.47 single crystal was calculated from the experimental X-ray diffraction (XRD) data, a = 0.6368 nm, and it perfectly matched with the value in cif file given in the ESI
Summary
Mg2Si and its alloys with Mg2Sn and Mg2Ge have attracted increasing area of interest for thermoelectric and optoelectronic applications due to affordability, nontoxicity and crustal abundance of their constituents.[1,2,3] In addition, these materials have a high absorption coefficient near their absorption edge and narrow energy band gap values in the range from 0.3 to 0.7 eV.[4,5,6,7,8] In that sense, they could be implemented as a secure option to the current toxic Hg-based IR sensors for night vision applications and short-wavelength IR light detection. Our results indicated the significance of Mg2Si0.53Ge0.47 crystal as a potential candidate for IR sensation and night vision applications
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