On the conduction mechanisms of Au/(Cu2O–CuO–PVA)/n-Si (MPS) Schottky barrier diodes (SBDs) using current–voltage–temperature (I–V–T) characteristics

Abstract

The temperature effect on the conduction mechanism of Au/Cu2O–CuO–PVA/n-Si (MPS) type Schottky barrier diodes (SBDs) have been investigated in detail in the wide temperature range of 100–380 K by using the forward bias current–voltage (I–V) measurements. It is observed that the semi logarithmic forward bias I–V plots have two distinct linear regions with different slopes for each temperature. These regions are called low bias region (LBR) and moderate bias region (MBR), respectively. The LBR and MBR correspond to (0.6–1.04 V) and (1.10–1.65 V) bias voltages, respectively. Main diode parameters such as reverse saturation current (I0), ideality factor (n) and zero-bias barrier height (Φb0) were calculated for these two regions. It is observed that the values of Φb0 increased as the values of n decreased with the increasing temperature and such behavior of Φb0 and n with temperature was attributed to the barrier inhomogeneities by assuming Gaussian distribution (GD) at the M/S interface. The Φb0 versus n and q/2kT plots were drawn to get an evidence of the GD. These two plots also have two linear regions at LBR and MBR. These regions are called the low temperature region (LTR) and high temperature region (HTR). Thus the mean values of barrier height (BH) and standard deviation (σs) were obtained by using the intercept and slope of these plots. After that, the conventional Richardson plot was drawn [(Ln(I0/T2) − q2σs 2/2k2T2) vs. q/kT] and it also has two linear regions. The main values of BH and effective Richardson constant (A*) were obtained from the slope and intercept of these plots. These values are found as 0.82 eV and 110.7 A/cm2 K2 for LTR and 1.53 eV and 115.5 A/cm2 K2 for HTR in the LBR and 0.77 eV and 111.9 A/cm2 K2 for LTR and 1.26 eV and 133.9 A/cm2 K2 for HTR in the MBR, respectively. The obtained values of A* are in good agreement with their theoretic values (112 A/cm2 K2) especially for HTR. Thus, the I–V–T characteristics of MPS type SBDs are successfully explained by the double GD model. Besides, the interface state density (Nss) of the MPS diode was calculated from forward-bias I–V measurements.