Browsing by Author "Türüt, A"

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Dependence of Thermal Annealing on the Density Distribution of Interface States in Ti/N-gaas(te) Schottky Diodes
(Elsevier Science Bv, 1999) Ayyildiz, E; Bati, B; Temirci, C; Türüt, A
The Ti/n-GaAs(Te) Schottky barrier diodes have been annealed in the temperature range 200-400 degrees C with steps of 100 degrees C for 5 min. The barrier height value has increased with increasing annealing temperature. This increase has been attributed to that the annealing removes the passivation effect of the native oxide layer and reactivates the surface defects which are responsible for the Fermi level pinning. The value of equilibrium interface charge density Q(ss)(0) has increased with increasing annealing temperature. It has been found that the experimental density distribution curves of the interface states and the values of equilibrium interface charge density Q(ss)(0) has confirmed this interpretation. The results indicate that the negative equilibrium interface charge is responsible for the actual equilibrium barrier height value. (C) 1999 Elsevier Science B.V. All rights reserved.
Determination of the Density Distribution of Interface States From High- and Low-Frequency Capacitance Characteristics of the Tin/Organic Pyronine-b/P-type Silicon Structure
(Wiley-v C H verlag Gmbh, 2002) Çakar, M; Temirci, C; Türüt, A
The interface state energy distribution curve of the Sn/ pyronine-B/p-Si Schottky diode has been obtained from its forward-bias C-HF and C-IF characteristics (see picture). The interface state density value rises exponentially with bias from the midgap towards the top of the valence band. The interface states and interfacial layer at the organic semiconductor/ inorganic semiconductor structures play an important role in the determination of the Schottky barrier height.
The Effect of Series Resistance on Calculation of the Interface State Density Distribution in Schottky Diodes
(Taylor & Francis Ltd, 2001) Ayyildiz, E; Temirci, C; Bati, B; Türüt, A
This work presents an attempt related to the importance of the fact that the series resistance value is considered in calculating the interface state density distribution from the non-ideal forward bias current-voltage (I-V) characteristics of Au/n-Si Schottky barrier diodes (SBDs). To examine the consistency of this approach, Au/n-Si SBDs with Si bulk thicknesses of 200 and 400 mum have been prepared. Both diodes showed non-ideal I-V behaviour with ideality factors of 1.14 and 1.12, respectively, and thus it has been thought that the diodes have a metal-interface layer-semiconductor configuration. At the same energy position near the bottom of the conduction band, the interface state density (N-SS) values, without taking into account the series resistance value of the devices, are almost one order of magnitude larger than the N-SS values obtained taking into account the series resistance value.
Effect of Thermal Annealing on Co/N-lec Gaas (Te) Schottky Contacts
(Pergamon-elsevier Science Ltd, 2000) Nuhoglu, Ç; Temirci, C; Bati, B; Biber, M; Türüt, A
The Co/n-GaAs(Te) Schottky barrier diodes have been annealed at temperatures from 100 to 300 degrees C for 5 min and from 350 to 800 degrees C for 1 min in N-2 atmosphere. Some expressions have been obtained to interpret the relation between the experiment barrier height Phi(b,o) and equilibrium interface charge density Q(ss)(0) depending on annealing temperature. The Phi(b,o) value has increased and Q(ss)(0) is decreased with increasing annealing temperature up to 550 degrees C. This increase in the barrier height has been attributed to the value of positive Q(ss)(0), which is responsible for the Fermi level pinning. The relation between the Phi(b,o), and Q(ss)(0) depending on annealing temperature is in very good agreement with that of the interface state density distribution especially in the mid-gap. (C) 2000 Elsevier Science Ltd. All rights reserved.
High-Barrier Height Sn/P-si Schottky Diodes With Interfacial Layer by Anodization Process
(Elsevier Science Bv, 2001) Temircl, C; Bati, B; Saglam, M; Türüt, A
We have fabricated the Sn/p-Si Schottky barrier diodes with different surface treatments. Prior to the Sn evaporation on the p-Si(0 0 1), the first kinds of samples consisted of a dip in diluted aqueous HF solution followed by a rinse in de-ionized water (sample 1, SDI), the second kinds of samples several steps of anodization in aqueous KOH solution each followed by a dip in diluted aqueous HF solution and a subsequent rinse in de-ionized water (sample 2, SD2), and the third kinds of samples one anodization step only (sample 3, SD3). We have found the lowest values of both the barrier heights and ideality factors with the diodes of preparation type SD2. The anodization, on the other hand, have increased both, the barrier heights as well as the ideality factors. The extrapolation of the barrier heights versus ideality factors plot to the ideality factor determined by the image force effect have given the laterally homogeneous barrier heights of approximately 0.75 and 0.92 eV for the SD2 and SD3 diodes. Furthermore, we have calculated a mean tunneling barrier height of (chi) = 0.12 eV for the MIS Sn/p-Si diodes with the anodic oxide layer. (C) 2001 Elsevier Science B.V. All rights reserved.
Low- and High-Frequency C-V Characteristics of the Contacts Formed by Sublimation of the Nonpolymeric Organic Compound on P-Type Si Substrate
(Wiley-v C H verlag Gmbh, 2004) Temirci, C; Çakar, M; Türüt, A; Onganer, Y
The Sn/pyronine-B/p-Si Schottky structures have been obtained by sublimation of the organic compound pyronine-B onto the top of a p-Si surface. Barrier height and ideality factor value of 0.79 eV and 1.13, respectively, for the device have been determined from the forward-bias current-voltage (I-V characteristics. The interface state density obtained from the forward bias high and low capacitance-voltage characteristics increases exponentially with bias between the midgap and the top of the valance band, from 2.15 x 10(11) cm(-2) eV(-1) at (0.79-E-v) eV to 1.16 x 10(12) cm(-1) eV(-1) at (0.53-E-v) eV. These values have been compared to those of the metal/Si structures in the literature, and it is seen that the presence of the nonreactive organic materials at the inorganic semiconductor and metal interface may obstruct the generation of the interface states at the semiconductor surface that strongly influence the Schottky barrier formation. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
The Schottky Barrier Height of the Rectifying Cu/Pyronline-b Au/Pyronine-b Sn/Pyronine-b and Al/Pyronine-b Contacts
(Elsevier Science Sa, 2004) Çakar, M; Temirci, C; Türüt, A
The Cu/pyronine-B/p-Si, Au/pyronine-B/p-Si, Al/pyronine-B/p-Si and Sn/pyronine-B/p-Si Schottky structures have been obtained by sublimation of the organic compound pyronine-B onto the top of p-Si surface. Our goal is to experimentally investigate whether or not a nonpolymeric organic compound as contact to an inorganic semiconductor such as Si can provide the continuous control of the barrier height (BH). The barrier height Phi(bp) values of 0.51, 0.674, 0.75 and 0.79 eV for the Cu/pyronine-B/p-Si, Au/pyronine-B/p-Si, Al/pyronine-B/P-Si and Sn/pyronine-B/p-Si Schottky structures have obtained from the forward current-voltage (I-V) characteristics. It has been seen that the values of Phi(bp) are significantly larger than those of conventional Schottky diodes. (C) 2003 Elsevier B.V. All rights reserved.
Temperature Dependence of the Current-Voltage Characteristics of the Al/Rhodamine-101 Contacts
(Elsevier, 2006) Karatas, S; Temirci, C; Çakar, M; Türüt, A
The current-voltage (I-V) characteristics of Al/Rhodamine-101/p-Si/Al contacts have been measured at temperatures ranging from 280 to 400 K at 20 K intervals. A barrier height (BH) value of 0.817 eV for the Al/Rh101/p-Si/Al contact was obtained at the room temperature that is significantly larger than the value of 0.58 eV of the conventional Al/p-Si Schottky diode. While the barrier height Phi(b0) decreases the ideality factors (n) become larger with lowering temperature. The high values of n depending on the sample temperature may be ascribed to decrease of the exponentially increase rate in current due to space-charge injection into Rh101 thin film at higher voltage. Therefore, at all temperatures, it has been seen that the I-V characteristics show three different regions, the ohmic behavior at low voltages, and the space charge limited current with an exponential distribution of traps at high voltages. (c) 2005 Elsevier B.V. All rights reserved.