Structural and functional properties of Zn(Ge,Sn)N2 thin films deposited by reactive sputtering

THIN SOLID FILMS

卷:709

Article

Beddelem, Nicole^1,2  Bruyere, Stephanie²  Cleymand, Franck²  Diliberto, Sebastien²  Longeaud, Christophe³  le Gall, Sylvain³  Templier, Roselyne¹  Miska, Patrice²  Hyot, Berangere¹ 

[1] Univ Grenoble Alpes, LETI, CEA, F-38000 Grenoble, France

[2] Univ Lorraine, IJL, CNRS, F-54000 Nancy, France

[3] Univ Paris Sud XI, Univ Pierre & Marie Curie, Cent Supelec, GEEPS,UMR 8507,CNRS, F-91190 Gif Sur Yvette, France

关键词: Zinc tin germanium nitride alloys;    Sputtering;    Optical bandgaps;    Tunable optical bandgap;    Optoelectronic applications;   

DOI  :  10.1016/j.tsf.2020.138192

来源: Elsevier

【 摘 要 】

Semiconductor alloys ZnSnxGe1-xN2 have theoretical crystal structure and electronic structure similar to that of InGaN alloys. These promises of direct and tunable band gaps are very attractive to unlock a suite of functionality for these nitride semiconductors, namely for the use in long wavelength light emitters and light absorbers for solar cells. We report here a structural, electrical and optical investigation of sputtered ZnSnxGe1-xN2 films for 0 <= x <= 1 by gradually substituting germanium with fin. Compared to InGaN alloys which suffer from a miscibility gap and exhibit phase segregation beyond similar to 20% In, ZnSn(x)Ge(1-x)N(2 )form advantageously a continuous alloy for 0 <= x <= 1. Its adjustable lattice parameter a (from 3.22 angstrom to 3.41 angstrom) according to Vegard's law as well as the linear variation of the vibration modes by Fourier transform infrared spectroscopy indicate that the ZnSnxGe1-xN2 alloying is achievable without phase separation. The single chemical environment measured by Mossbauer spectroscopy for Sn4+ ions, whatever Sn content in ZnSnxGe1-xN2, confirms the continuous nature of alloying. Samples exhibit semiconducting properties, including optical band gaps and electronic behaviors with temperature. The experimental observations show that the resistivity in ZnSnxGe1-xN2 alloys can cover several orders of magnitude from a quasi-metallic (for ZnSnN2) to a quasi-insulating (for ZnGeN2) behavior and that the band gap is tunable from 2.1 eV to 3.04 eV with a nearly linear dependence on the composition. Thus, ZnSnxGe1-xN2 materials offer a solution for bandgap tunability in nitride semiconductors, and may enable enhanced functionality such as efficient green and red light emitters and light absorbers for photosynthetic devices.

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