scholarly journals Ferromagnetic Schottky Contact for GaN Based Spin Devices

2021 ◽  
Vol 12 ◽  
pp. 55-60
Author(s):  
Tarkeshwar C. Patil

In this paper, ferromagnetic Schottky contacts for GaN based spin injection are being studied. The electrical characterization of this Co/n-GaN and Fe/n-GaN Schottky contacts showing the zero-bias barrier height comes closer to unity as the temperature is increased. Also, the Richardson constant is extracted for this Schottky contact. Both the zero-bias barrier height and the Richardson constant are verified both experimentally as well as theoretically. Thus, this Schottky contacts will serve as spin injector for GaN based spin devices specifically for GaCrN based devices

2018 ◽  
Vol 96 (7) ◽  
pp. 816-825 ◽  
Author(s):  
H.H. Güllü ◽  
M. Terlemezoğlu ◽  
Ö. Bayraklı ◽  
D.E. Yıldız ◽  
M. Parlak

In this paper, we present results of the electrical characterization of n-Si/p-Cu–Zn–Se hetero-structure. Sputtered film was found in Se-rich behavior with tetragonal polycrystalline nature along with (112) preferred orientation. The band gap energy for direct optical transitions was obtained as 2.65 eV. The results of the conductivity measurements indicated p-type behavior and carrier transport mechanism was modelled according to thermionic emission theory. Detailed electrical characterization of this structure was carried out with the help of temperature-dependent current–voltage measurements in the temperature range of 220–360 K, room temperature, and frequency-dependent capacitance–voltage and conductance-voltage measurements. The anomaly in current–voltage characteristics was related to barrier height inhomogeneity at the interface and modified by the assumption of Gaussian distribution of barrier height, in which mean barrier height and standard deviation at zero bias were found as 2.11 and 0.24 eV, respectively. Moreover, Richardson constant value was determined as 141.95 Acm−2K−2 by means of modified Richardson plot.


1996 ◽  
Vol 448 ◽  
Author(s):  
N. Marcano ◽  
A. Singh

AbstractIn/n-In0.46Ga0.54P Schottky diode was fabricated by thermal evaporation of In on chemically etched surface of In0.45Ga0.54P:Si epitaxial layer grown on highly doped n type GaAs. The In metal formed a high quality rectifying contact to In0.46Ga0.54P:Si with a rectification ratio of 500. The direct current-voltage/temperature (I-V/T) characteristics were non-ideal with the values of the ideality factor (n) between 1.26-1.78 for 400>T>260 K. The forward I-V data strongly indicated that the current was controlled by the generation-recombination (GR) and thermionic emission (TE) mechanisms for temperature in the range 260-400 K. From the temperature variation of the TE reverse saturation current, the values of (0.75±0.05)V and the (4.5±0.5)×10-5 Acm-2K-2 for the zero bias zero temperature barrier height (φoo) and modified effective Richardson constant were obtained. The 1 MHz capacitance-voltage (C-V) data for 260 K < T < 400 K was analyzed in terms of the C-2-V relation including the effect of interface layer to obtain more realistic values of the barrier height (φbo). The temperature dependence of φbo was described the relation φbo =(0.86±10.03) - (8.4±0.7)×l0-4T. The values of φoo, obtained by the I-V and C-V techniques agreed well.


2015 ◽  
Vol 821-823 ◽  
pp. 436-439 ◽  
Author(s):  
Razvan Pascu ◽  
Gheorghe Pristavu ◽  
Gheorghe Brezeanu ◽  
Florin Draghici ◽  
Marian Badila ◽  
...  

The electrical behavior and stability of a temperature sensor based on 4H-SiC Schottky diodes using Ni2Si as Schottky contact, are investigated. The ideality factor and the barrier height were found to be strongly dependent on the post-annealing temperature of the Ni contact (which lead to the formation of Ni2Si). A nearly ideal Schottky device, with the barrier height approaching the high value of1.7eV, and a slight temperature dependence, was obtained after an annealing atTA=800°C.This high barrier height proves that Ni2Si is suitable as Schottky contact for temperature sensors, able to reliably operate up to450°C. Sensor sensitivity levels between1.00mV/°Cand2.70 mV/°Chave been achieved.


2015 ◽  
Vol 821-823 ◽  
pp. 986-989
Author(s):  
Gabriele Fisichella ◽  
Giuseppe Greco ◽  
Fabrizio Roccaforte ◽  
Filippo Giannazzo

A nanoscale electrical characterization of graphene (Gr) contacts to AlxGa1-xN/GaN heterostructures has been carried out using conductive atomic force microscopy. The impact of the AlGaN microstructure on the current transport at Gr/AlGaN interface was evaluated considering two Al0.25Ga0.75N/GaN heterostructures with very different quality in terms of surface roughness and defectivity, i.e. a uniform and defect-free sample and a sample with a high density of V-defects, that locally cause a reduction of the AlGaN thickness. Rectifying contacts were found on the bare (Gr-free) AlGaN surfaces of both samples, but with a more inhomogeneous and lower Schottky barrier height (ΦB≈0.6 eV) in the presence of V-defects with respect to the case of the uniform AlGaN (ΦB≈0.9 eV). Very different electrical behaviour was observed for Gr on the two AlGaN samples, i.e. a low barrier height Schottky contact (ΦB≈0.4 eV) for the uniform AlGaN and an Ohmic contact for the defective AlGaN. Both Schottky and ohmic Gr/AlGaN contacts exhibit an excellent lateral uniformity, that can be ascribed to an averaging effect of the Gr electrode over the AlGaN interfacial inhomogeneities.


2006 ◽  
Vol 89 (24) ◽  
pp. 242117 ◽  
Author(s):  
H. B. Yao ◽  
D. Z. Chi ◽  
R. Li ◽  
S. J. Lee ◽  
D.-L. Kwong

2013 ◽  
Vol 86 ◽  
pp. 17-21 ◽  
Author(s):  
B.P. Downey ◽  
D.J. Meyer ◽  
D.S. Katzer ◽  
D.F. Storm ◽  
S.C. Binari

2014 ◽  
Vol 778-780 ◽  
pp. 1142-1145 ◽  
Author(s):  
Filippo Giannazzo ◽  
Stefan Hertel ◽  
Andreas Albert ◽  
Antonino La Magna ◽  
Fabrizio Roccaforte ◽  
...  

Epitaxial graphene fabricated by thermal decomposition of the Si-face of silicon carbide (SiC) forms a defined interface to the SiC substrate. As-grown monolayer graphene with buffer layer establishes an ohmic interface even to low-doped (e. g. [N] ≈ 1015 cm-3) SiC, and a specific contact resistance as low as ρC = 5.9×10-6 Ωcm2 can be achieved on highly n-doped SiC layers. After hydrogen intercalation of monolayer graphene, the so-called quasi-freestanding graphene forms a Schottky contact to n-type SiC with a Schottky barrier height of 1.5 eV as determined from C-V analysis and core level photoelectron spectroscopy (XPS). This value, however, strongly deviates from the respective value of less than 1 eV determined from I-V measurements. It was found from conductive atomic force microscopy (C-AFM) that the Schottky barrier is locally lowered on other crystal facets located at substrate step edges. For very small Schottky contacts, the barrier height extracted from I-V curves approaches the value of 1.5 eV from C-V and XPS.


2010 ◽  
Vol 7 (7-8) ◽  
pp. 2007-2009 ◽  
Author(s):  
Yoshitaka Nakano ◽  
Nobuyuki Matsuki ◽  
Yoshihiro Irokawa ◽  
Masatomo Sumiya

2012 ◽  
Vol 90 (1) ◽  
pp. 73-81 ◽  
Author(s):  
V. Lakshmi Devi ◽  
I. Jyothi ◽  
V. Rajagopal Reddy

In this work, we have investigated the electrical characteristics of Au–Cu–n-InP Schottky contacts by current–voltage (I–V) and capacitance–voltage (C–V) measurements in the temperature range 260–420 K in steps of 20 K. The diode parameters, such as the ideality factor, n, and zero-bias barrier height, Φb0, have been found to be strongly temperature dependent. It has been found that the zero-bias barrier height, Φb0(I–V), increases and the ideality factor, n, decreases with an increase in temperature. The forward I–V characteristics are analyzed on the basis of standard thermionic emission (TE) theory and the assumption of gaussian distribution of barrier heights, due to barrier inhomogeneities that prevail at the metal–semiconductor interface. The zero-bias barrier height Φb0 versus 1/2kT plot has been drawn to obtain the evidence of a gaussian distribution of the barrier heights. The corresponding values are Φb0 = 1.16 eV and σ0 = 159 meV for the mean barrier height and standard deviation, respectively. The modified Richardson plot has given mean barrier height, Φb0, and Richardson constant, A**, as 1.15 eV and 7.34 Acm−2K−2, respectively, which is close to the theoretical value of 9.4 Acm−2K−2. Barrier heights obtained from C–V measurements are higher than those obtained from I–V measurements. This inconsistency between Schottky barrier heights (SBHs) obtained from I–V and C–V measurements was also interpreted. The temperature dependence of the I–V characteristics of the Au–Cu–n-InP Schottky diode has been explained on the basis of TE mechanism with gaussian distribution of the SBHs.


2009 ◽  
Vol 615-617 ◽  
pp. 651-654 ◽  
Author(s):  
C. Koliakoudakis ◽  
J. Dontas ◽  
S. Karakalos ◽  
M. Kayambaki ◽  
S. Ladas ◽  
...  

The behavior of 200nm Cr Schottky contacts on n-type 4H-SiC has been investigated with photoelectron spectroscopy (XPS) and standard (I-V and C-V) electrical measurements at different measurement temperatures. A barrier height close to 1.2 eV was calculated from XPS data under no-current and no-bias conditions on ultra-thin Cr films grown in-situ under UHV conditions. The I-V measurements on as-deposited contacts resulted in a barrier height of 1.06 eV while a value of 1.2 eV has been extracted from the C-V measurements.


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