On the temperature dependent current transport mechanisms and barrier inhomogeneity in Au/SnO2–PVA/n-Si Schottky barrier diodes

Autor: Çiğdem Bilkan, Yashar Azizian-Kalandaragh, S. Fotouhi-Shablou, Ş. Altındal, Y. Badali
Rok vydání: 2017
Předmět:
Zdroj: Applied Physics A. 123
ISSN: 1432-0630
0947-8396
DOI: 10.1007/s00339-017-1168-y
Popis: In this paper, we report the preparation and characterization of SnO2–PVA nanocomposite film as interlayer for Schottky barrier diodes (SBDs). The possible current transport mechanisms (CTMs) of the prepared SBDs were investigated using the forward-bias current–voltage (I–V) characteristics in the temperature range of 80–400 K. The structure of nanocomposite film was characterized by an X-ray diffractometer (XRD) and the surface morphology was investigated using a Scanning Electron Microscopy (SEM) at room temperature. The values of ideality factor (n) and zero-bias barrier height ( $$\overline{\varPhi }_{\text{Bo}}$$ ) showed variation with temperature, such that they changed from 19.10 to 3.77 and 0.190 to 0.844 eV, respectively. $$\overline{\varPhi }_{\text{Bo}}$$ –n, $$\overline{\varPhi }_{\text{Bo}}$$ −q/2kT, and n −1−q/2kT plots were drawn to get evidence to the Gaussian Distribution (GD) of the barrier height (BH). These plots revealed two distinct linear regions with different slopes for low temperatures (80–160 K) (LTs) and high temperatures (180–400 K) (HTs). This behavior is an evidence to the existence double GD of BHs which provides an average value for BH ( $$\overline{\varPhi }_{\text{Bo}}$$ ) and a standard deviation (σs) for each region. The high value of n especially at low temperatures was attributed to the existence of interlayer: interface states (N ss) and barrier inhomogeneity at Au/n-Si interface. The values of $$\overline{\varPhi }_{\text{Bo}}$$ and σs were obtained from the intercept and slope of mentioned plots as 0.588 and 0.0768 V for LTs and 1.183 eV and 0.158 V for HTs, respectively. Moreover, the modified ln(I s/T 2)−q 2σ s 2 /2k 2 T 2 vs q/kT plot also showed two linear regions. The values of $$\overline{\varPhi }_{\text{Bo}}$$ and effective Richardson constant (A *) were extracted from the slope and intercept of this plot as 0.610 eV and 93.13 A/cm2 K2 for LTs and 1.235 eV and 114.65 A/cm2 K2 for HTs, respectively. The value of A* for HTs is very close to the theoretical value (112 A/cm2 K2) of n-type Si. Thus, the forward-bias I–V–T characteristics of Au/SnO2–PVA/n-Si (SBDs) were successfully explained in terms of the thermionic-emission (TE) mechanism with a double GD of BHs.
Databáze: OpenAIRE
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