Fig. 2: Tunable polarized MIR emission from band crossing in Te.
a The schematic illustration of the GrT/Te/GrB heterostructure LED. Band diagram of GrT/Te/GrB under operational bias. \({hv}\): The energy of emitted photons. b Contour maps of electroluminescence (EL) spectra as a function of reverse bias and forward bias at 78 K. c The corresponding PL spectrum of Te in GrT/Te/GrB heterostructure. d Semi-logarithmic plot of EL intensity (blue) and current density jd (red) as a function of bias voltage Vd. e Bias-dependent EL spectra. f Normalized EL spectra of GrT/Te/GrB at different Vd. FWHM: Full width at half maximum. kB: Boltzmann constant. T: Temperature. g Semi-log plots of normalized EL intensity versus photon energy. The lines are linear fits to the corresponding data. h Polar plot of the normalized EL intensity at different Vd, demonstrating polarization tunability. i DOP of GrT/Te/GrB LED as a function of jd. The error bars indicate the standard deviation of the DOP, obtained from three independent measurements of EL intensity and calculated using the error propagation formula for \({{\rm{DOP}}}=({{{|p}}_{{vck}}^{x}|}^{2}-{{{|p}}_{{vck}}^{z}|}^{2})/({{{|p}}_{{vck}}^{x}|}^{2}+{{{|p}}_{{vck}}^{z}|}^{2})\).
