ZnSe/Al/ZnSe nanosandwiched structures as dual Terahertz-Gigahertz signal receivers

Abstract

In the current work, we focus on the enhancements in performance of the ZnSe terahertz/gigahertz signal receivers which are achieved by the insertion of nanosheets of Al layers of thickness of 30 nm between two 500 nm thick layers of ZnSe. The Al nanosandwiching which decreased the defect density, stacking faults and increased the grain size in the films increased the optical conductivity by more than 125%, increased the drift mobility to 313 cm(2) V-1 s(-1) and widens the plasmon frequency ranges to 0.49-4.92 GHz. In addition, the analysis of the terahertz cutoff (f(co)) frequency spectra have shown that the presence of Al nanosheets improves the cutoff frequency value by three orders of magnitude making the ZnSe receivers more suitable for visible light and IR communication technology. The value of f(co) is 49.6 THz when light signal of wavelengths of 408 nm that suits blue lasers is irradiated. Moreover, the impedance spectroscopy analysis in the gigahertz frequency domain has shown that the Al sandwiched ZnSe exhibits negative capacitance spectra in the frequency domain of 0.01-1.04 GHz. This property is useful for parasitic capacitance cancelling and noise reducing in circuits. Furthermore, the study of the microwave cutoff frequency spectra has shown that the value of f(co) is enhanced by three orders of magnitude above 1.5 GHz.