Synthesis and characterization of pure and graphene (Gr)-doped organic/polymer nanocomposites to investigate the electrical and photoconductivity properties of Au/n-GaAs structures


Cicek O., Tecimer H. , Tan S. O. , Tecimer H., Orak I., Altindal S.

Composites Part B: Engineering, cilt.113, ss.14-23, 2017 (SCI Expanded İndekslerine Giren Dergi) identifier

Özet

In the present study, Schottky diodes (SDs) were produced with and without interlayer to evaluate synthesis and characterization of pure and graphene (Gr)-doped organic/polymer nanocomposites on the electrical (i.e. ideality factor (n), saturation current (I-o), barrier height (Phi(Bo)), shunt (R-sh) and series (R-s) resistances) and photoconductivity (i.e. photocurrent (I-ph), responsivity (R), photoconductivity sensitivity (S-ph), photosensitivity) parameters of Au/n-GaAs devices. Electrical parameters of Au/n-GaAs (MS) type (D-1), Au/pure PVA/n-GaAs (MPS) type (D-2) and Au/Gr-doped PVA/n-GaAs (MPS) type (D-3) structures have been obtained to the current-voltage (I-V) measurements using thermionic emission (TE) theory, Cheung's method and modified Norde's methods and, moreover, compared each other. The resistance (R-i) for these SDs was additionally calculated from Ohm's law as function of voltage for each diode. Experimental research indicate that there is an increase in R-sh value and a decrease in R-s value and rectifier rate (RR = I-F/I-R) for Gr-doped PVA structure according to the pure PVA structure, when the values of R-s and R-sh are compared between each other. Also, the Phi(Bo) values for D-2 and D-3 type SDs is lower than that of D-1 type SDs. The value of R-s for Gr-PVA interlayer 286 times lower than without interlayer. Therefore, it can be said that the PVA (pure and Gr-doped) interfacial layer effectively modified the barrier height (BH) according to without interlayer. As photoconductivity properties for SDs, the I-ph values in the reverse bias increased with illumination intensities (50-200 W). On the other hand, it is clear that there are an increase for D-2 and D-3 and a decrease for D1 with increasing illumination intensities in the R and S-ph values. So, they are sensitive to illumination intensities and exhibit a photoconductivity effect. As a result, Gr-doped PVA interlayer substantially got better the quality and performance of Au/PVA/n-GaAs SDs. (C) 2017 Elsevier Ltd. All rights reserved.