Fabrication and characterization of Au/n-type InP Schottky barrier diode with monolayer graphene interlayer

Abstract

Au/graphene/n-InP Schottky barrier diode (SBD) was fabricated by the use of spray pyrolysis technique with a monolayer graphene interlayer, and the temperature dependent characteristics was performed in a wide temperature range from 60 to 300 K with steps. The Au/GR/n-InP SBD exhibited excellent rectifying behavior however barrier height (Φ b0 ) of the device increased with increasing temperature while ideality factor (n) and series resistance (R s ) decreased. The strong temperature dependency of SBH and the deviation from theoretical value of Richardson constant clarified by considering a Gaussian distribution model of the SBH which was caused by the BH inhomogeneities. The mean BH F b0 of 0.94 and 0.59 eV was estimated with the standard deviation of 0.011 and 0.004 eV attributed to the presence of a double GD of SBD. The modified Richardson plots gave mean BH value of 0.98 and 0.70 eV and the Richardson constant values of 8.10, 13,38 A K −2 cm −2 was very close to its theoretical value of 9.4 A K −2 cm −2 . These results yields that carrier transport mechanism of Au/GR/n-InP SBD can be clarified by Thermionic-emission-diffusion (TED) mechanism with a double Gaussian distribution of the SBHs. In addition, the I-V characteristics of SBD under dark and light ambiance indicates that Au/graphene/n-InP is strongly dependent on the light effect. Thus, we can conclude that graphene/n-InP device is a potential candidate for photovoltaic systems. Moreover, the UV-vis spectroscopy of the graphene film exhibit a strong absorption as A=9.45% compared to the literature, that is, Au/GR/n-InP SBD grown by spray pyrolysis has excellent optical properties for optoelectronic applications.

The Structural, Optical, and Electrical Characterization of Ti/n‐InP Schottky Diodes with Graphene Oxide Interlayer Deposited by Spray Pyrolysis Method

“…The Schottky diode parameters such as the ideality factor, BH, saturation current, and Richardson constant can be obtained from the classical method of analyzing the experimental I–V characteristics. [ 23,24 ] Particularly, the ideality factor and the BH are determined from the general equation of the current transport density which is usually described within the well‐known thermionic emission (TE) theory given in Equation () [ 23 ] where I 0 is the saturation current determined from extrapolating the linear region of the I–V plots and defined bywhere n is the ideality factor which is dimensionless, V is the applied bias voltage, q is the electronic charge, k is the Boltzmann constant ( k = 8.625 × 10 −5 eV K −1 ), T is the absolute temperature (Kelvin), A is the rectifier contact area ( r = 0.25 mm), A * is the effective Richardson constant (9.4 A cm −2 K −2 for n‐type InP), [ 25,26 ] and Φ b 0 is the experimental apparent BH. From Equation (), it can be written as…”

“…It was reported that BH inhomogeneity has been explained by many current‐transmission mechanisms. [ 25 ] However, it is clear that these explanations are not sufficient. The increase in the ideality factor at low temperatures cannot be explained just by the interface layer thickness or interface conditions.…”

“…Especially at low temperatures, the Gaussian distribution function is the most usual and highly applicable method for clarifying the abnormal characteristics of the SBDs. [ 25 ] In the Gaussian distribution for a SBD with a BH and its standard deviation , these parameters are linearly connected to the bias voltage and for such a distribution Φ ap is the zero bias apparent BH and n ap is the apparent ideality factor. In ideal condition ( n = 1), Φ ap and n ap parameters are given by ref.…”