Design and Electrical Performance of Cds/Sb<sub>2< Tunneling Heterojunction Devices
No Thumbnail Available
Date
2018
Journal Title
Journal ISSN
Volume Title
Publisher
Iop Publishing Ltd
Open Access Color
OpenAIRE Downloads
OpenAIRE Views
Abstract
In the current work, a tunneling barrier device made of 20 nm thick Sb2Te3 layer deposited onto 500 nm thick CdS is designed and characterized. The design included a Yb metallic substrate and Ag point contact of area of 10(-3) cm(2). The heterojunction properties are investigated by means of x-ray diffraction and impedance spectroscopy techniques. It is observed that the coating of the Sb2Te3 onto the surface of CdS causes a further deformation to the already strained structure of hexagonal CdS. The designed energy band diagram for the CdS/Sb2Te3 suggests a straddling type of heterojunction with an estimated conduction and valence band offsets of 0.35 and 1.74 eV, respectively. In addition, the analysis of the capacitance-voltage characteristic curve revealed a depletion region width of 14 nm. On the other hand, the capacitance and conductivity spectra which are analyzed in the frequency domain of 0.001-1.80 GHz indicated that the conduction in the device is dominated by the quantum mechanical tunneling in the region below 0.26 GHz and by the correlated barrier hopping in the remaining region. While the modeling of the conductivity spectra allowed investigation of the density of states near Fermi levels and an average scattering time of 1.0 ns, the capacitance spectra exhibited resonance at 0.26 GHz followed by negative differential capacitance effect in the frequency domain of 0.26-1.8 GHz. Furthermore, the evaluation of the impedance and reflection coefficient spectra indicated the usability of these devices as wide range low pass filters with ideal values of voltage standing wave ratios.
Description
Khanfar, Hazem k./0000-0002-3015-4049; Qasrawi, Atef Fayez/0000-0001-8193-6975
Keywords
straddling barrier, Sb2Te3, impedance
Turkish CoHE Thesis Center URL
Fields of Science
Citation
41
WoS Q
Q3
Scopus Q
Source
Volume
5
Issue
2