Planar, broadband, and tunable hot-electron photodetection with chromium-involved Tamm plasmons

Abstract Planar hot-electron photodetectors (HE PDs) often operate at specified working wavelengths at which devices exhibit high optical absorption efficiencies. Recently, several planar HE PDs with strong optical absorptions across broad wavelength ranges have been demonstrated. However, the studies about spectral tunability of broadband HE PDs remain scarce and planar hot-electron photodetection with customized spectral linewidths are still absent. Herein, we propose a Tamm plasmon (TP) design of planar, broadband, and tunable HE PDs that have a thin Cr film on a distributed Bragg reflector. Optical investigations show that the thickness of dielectric layer adjacent to Cr layer is a critical factor in determining TP-induced optical responses, including prominent anti-reflection characteristic and broadband strong absorption in the Cr layer. Subsequent electrical analysis verify that device electrical spectra are strongly related to the thickness of critical dielectric layer that have great effects on spectral properties about electronic processes. Comparison studies between the designed Cr-involved device and referenced Au-involved device highlight the superiority of the designed device in high average responsivity and variable broad linewidth.