Metal-insulator-semiconductor (MIS) structures have been investigated theirs good applications in electronic and optoelectronic. Their importance attributes that they have storage layer property, capacitance effect and high dielectric constant. For this reason, two samples of Si3N4 layers were deposited with plasma-enhanced chemical vapor deposition (PECVD) technique on p-type Si; first is about 5 nm thickness and the other is about 50 nm. The thicknesses of Si3N4 were adjusted by an ellipsometer. It was studied the thickness effect of Si3N4 layers on the Al/Si3N4/p type Si contact and acquired the capacitance-voltage (C–V) and conductance–voltage (G−V) characteristics of the structures in the frequency and applied bias voltage ranges of 10 kHz to 1 MHz and −5 V to +5 V, respectively, at room temperature. Changing of Si3N4 layer thickness could be seen that influenced characterizations of the contacts. In each contact having different insulator layers, capacitance values decreased and conductance values increased with increasing frequencies. The interface states (Nss), the effect of series resistance (Rs), barrier height (Φb) and carrier concentration (Na) were found from characterizations and explained. It was also measured and compared C–V and G−V characterizations dual measurement at 500 kHz in the room temperature for 5 nm and 50 nm thicknesses layers. It could be seen that they have similarly memristor structure and can be used and improved for memory devices.

Abstract

The ZnO layer onto n-Si has been formed by atomic layer deposition technique. A final film thickness of 10 nm has been obtained by the resulting ZnO film growth rate of about 1.45 Å per cycle. The crystal structures of the ZnO layer were acquired by X-ray diffractometer (XRD) and it could be seen ZnO peaks from XRD patterns. The surface of ZnO thin film onto the n-Si could be seen with Atomic Force Microscopy (AFM) images and it were obtained homogenous and smooth surface. The I-V measurements were performed -2V to +2 V under dark and light, C-V measurements were performed changing 10 kHz to 2 MHz frequency and -2 V to +2 V bias voltage at room temperature. The device has the saturation current value of 8.99 × 10-9 A. The values of ideality factor (n ) and the barrier height (?b) have been found to be 2.49 and 0.77 eV by using the thermionic emission theory, respectively. In addition, the barrier height ?b and the series resistance (Rs) have been also acquired from Cheung's functions. The photovoltaic parameters of device; short circuit current (Isc), open circuit voltage (Voc), fill factor (FF) and conversion efficiency (?) were taken as 342 mV, 34.7 µA, 32% and 0.48% under 100 mW/cm2 light intensity, respectively. The C–V and G–V plots of device almost have peaks in all frequencies except for 2 MHz frequency. The device also behaved like memristor at 500 kHz dual C–V measurements under dark and light but has not wide memory window. It has been concluded that the device can be used as photodiode at room temperature because of small saturation current and good rectifying behavior and it may be improved photovoltaic, capacitor and memristor properties of Au/ZnO/n-Si device in the future