Capacitance-conductance characteristics of Au/Ti/Al2O3/n-GaAs structures with very thin Al2O3 interfacial layer

High-k Al2O3 with metallic oxide thickness of about 3 nmon n-type GaAs substrate has been deposited by the atomic layer deposition (ALD) technique. Thus, it has been formed the Au-Ti/Al2O3/n-GaAs MIS structures. It has been seen that the MIS structure exhibits excellent capacitance-voltage (C-V) and current-voltage (I-V) properties at 300 K. The saturation current of the forward bias and reverse bias I-V characteristics was the same value. An ideality factor value of 1.10 has been obtained from the forward bias I-V characteristics. The C-Vcharacteristics of the structure have shown almost no hysteresis from +3 Vto -10 Vwith frequency as a parameter. The reverse biasC-V curves have exhibited a behavior without frequency dispersion and almost hysteresis at each frequency from 10 kHz to 1000 kHz. © 2015 IOP Publishing Ltd

Effect of different sound atmospheres on SnO2:Sb thin films prepared by dip coating technique

Different sound atmosphere effects were investigated on SnO2:Sb thin films, which were deposited with dip coating technique. Two sound atmospheres were used in this study; one of them was nay sound atmosphere for soft sound, another was metallic sound for hard sound. X-ray diffraction (XRD) graphs have indicated that the films have different orientations and structural parameters in quiet room, metallic and soft sound atmospheres. It could be seen from UV-Vis spectrometer measurements that films have different band gaps and optical transmittances with changing sound atmospheres. Scanning electron microscope (SEM) and AFM images of the films have been pointed out that surfaces of films have been affected with changing sound atmospheres. The electrical measurements have shown that films have different I-V plots and different sheet resistances with changing sound atmospheres. These sound effects may be used to manage atoms in nano dimensions. © 2017 World Scientific Publishing Company

Capacitance-conductance-current-voltage characteristics of atomic layer deposited Au/Ti/Al<inf>2</inf>O<inf>3</inf>/n-GaAs MIS structures

We have studied the admittance and current-voltage characteristics of the Au/Ti/Al2O3/n-GaAs structure. The Al2O3 layer of about 5 nm was formed on the n-GaAs by atomic layer deposition. The barrier height (BH) and ideality factor values of 1.18 eV and 2.45 were obtained from the forward-bias ln I vs V plot at 300 K. The BH value of 1.18 eV is larger than the values reported for conventional Ti/n-GaAs or Au/Ti/n-GaAs diodes. The barrier modification is very important in metal semiconductor devices. The use of an increased barrier diode as the gate can provide an adequate barrier height for FET operation while the decreased barrier diodes also show promise as small signal zero-bias rectifiers and microwave. The experimental capacitance and conductance characteristics were corrected by taking into account the device series resistance Rs. It has been seen that the non-correction characteristics cause a serious error in the extraction of the interfacial properties. Furthermore, the device behaved more capacitive at the reverse bias voltage range rather than the forward bias voltage range because the phase angle in the reverse bias has remained unchanged as 90°independent of the measurement frequency. © 2015 Elsevier Ltd. All rights reserved

Temperature-dependent I-V characteristics in thermally annealed Co/p-InP contacts

We prepared the sputtered Co/p-InP Schottky diodes which consisted of as-deposited, and diodes annealed from 200 °C to 700 °C. The annealed samples were cooled from the annealing temperature down to room temperature, and then, their current-voltage (I-V) characteristics were measured. Schottky barrier height (SBH) at 300 K slightly decreases from 0.80 eV (for as-deposited sample) down to 0.77 eV (for the sample annealed at 400 °C) with the annealing temperature and then again increases up to 0.91 eV for the sample annealed at 700 °C. The I-V measurements were made in the sample temperature range of 60–400 K. It is seen that the SBH for each diode monotonically increases with increasing the sample temperature up to 400 K. In the sample temperature range of 60–400 K, the Co/p-InP SBD annealed at 400 °C has a lower ideality factor value than those of the as-deposited and 200 °C annealed SBDs at each sample temperature. Thus, remarkable apparent improvement of the diode parameters has been achieved by means of the thermal annealing. The improvement in the Co/p-InP interface due to the thermal annealing process has continued without deteriorating at each measurement temperature from 60 K to 400 K. Therefore, it has been concluded that the thermal annealing process translates the MS Schottky contacts into thermally more stable Schottky contacts