| Abstrakt: |
In this study, the electrical and optoelectronic properties of aluminium/2-hydroxybenzaldehyde phenylhydrazone/aluminium two-terminal metal–semiconductor–metal (M–S–M) planar structure are investigated. In the electrical study, the device has shown nonlinear current–voltage characteristics, similar to a diode. The current conduction mechanism within the device is explained considering the thermionic emission model of dual metal–semiconductor back-to-back rectifying contacts. In the optoelectronic investigation, the device has exhibited wavelength-dependent photosensitivity. During the exposure around 458 nm, 527 nm, and 943 nm of continuous illuminations, a definite time-dependent increase in the device current is observed under a fixed dc bias condition. This fact confirms a definite reduction of the device resistance under illumination. The matter is explained in terms of the photo-generation of excess hole and electron concentrations within 2-hydroxybenzaldehyde phenylhydrazone layer. In the alternating current analyses, the measured zero bias capacitance of the test structure has shown a prominent frequency dependency at relatively lower frequencies, which become insignificant at higher frequencies. Moreover, the capacitance of the M–S–M device has shown an increasing trend with the development of applied voltage. Studies on the transient behaviour have revealed an explicit frequency-selective nature of the fabricated M–S–M test structure under a set of square waves ranging between 700 Hz and 1 MHz. [ABSTRACT FROM AUTHOR] |
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