Physical Design and Dynamical Analysis of Resonant–Antiresonant Ag/MgO/GaSe/Al Optoelectronic Microwave Devices

Abstract

In this work, the design and optical and electrical properties of MgO/GaSe heterojunction devices are reported and discussed. The device was designed using 0.4-lm-thick n-type GaSe as substrate for a 1.6-lm-thick p-type MgO optoelectronic window. The device was characterized by means of ultravioletvisible optical spectrophotometry in the wavelength region from 200 nm to 1100 nm, current-voltage (I-V) characteristics, impedance spectroscopy in the range from 1.0 MHz to 1.8 GHz, and microwave amplitude spectroscopy in the frequency range from 1.0 MHz to 3.0 GHz. Optical analysis of the MgO/GaSe heterojunction revealed enhanced absorbing ability of the GaSe below 2.90 eV with an energy bandgap shift from 2.10 eV for the GaSe substrate to 1.90 eV for the heterojunction design. On the other hand, analysis of I-V characteristics revealed a tunneling-type device conducting current by electric fieldassisted tunneling of charged particles through a barrier with height of 0.81 eV and depletion region width of 670 nm and 116 nm when forward and reverse biased, respectively. Very interesting features of the device are observed when subjected to alternating current (ac) signal analysis. In particular, the device exhibited resonance-antiresonance behavior and negative capacitance characteristics near 1.0 GHz. The device quality factor was $10 2 . In addition, when a small ac signal of Bluetooth amplitude (0.0 dBm) was imposed between the device terminals, the power spectra of the device displayed tunable band-stop filter characteristics with maximum notch frequency of 1.6 GHz. The energy bandgap discontinuity, the resonance-antiresonance behavior, the negative capacitance features, and the tunability of the electromagnetic power spectra at microwave frequencies nominate the Ag/MgO/ GaSe/Al device as a promising optoelectronic device for use in multipurpose operations at microwave frequencies.

Optical NIR-VIS-VUV constants of advanced substrates for thin-film devices

“…MgO is transparent in the near IR and through the visible and UV ranges up to a photon energy of 7.5 eV. In comparison with other substrates, MgO has a low index of refraction throughout the entire visible range and as a result has been proven useful in many optoelectronic applications [59,60].…”

Characterization of As2Se3/MoO3 heterojunction designed for multifunctional operations

“…However, analysis of the current-voltage characteristics in accordance with the Schottky-Richardson approaches revealed that the current is dominated by the electric field assisted thermionic emission (tunneling) of charge carriers through electric field dependent potential barriers (F) was tested using the respective equations [31], In these equations, f 0 is the zero field value, A* =120 m* is the Richardson constant, w is the net effective width of the interface depletion region. Under the conditions were the Schottky-Richardson field emission mechanism dominates, the ideality factor n=η=1, γ=0 are substituted [31,32]. Employing equations (1) and (2) and plotting the ( ) -I V ln variations for forward and reverse biased devices reveals the linear slopes which are shown in figures 8(a) and (b), respectively.…”