Value Of Richardson Constant Research Articles

Electrical characterization of current conduction in Au/TiO2/n-Si at wide temperature range

In this study, we have examined Au/TiO 2 /n-Si Schottky barrier diodes (SBDs), in order to interpret in detail the experimental observed non-ideal current–voltage–temperature ( I–V–T ) characteristics. I–V characteristics were measured in the wide temperature range of 80–400 K. TiO 2 was deposited on n-Si substrate by reactive magnetron sputtering. The zero-bias barrier height ( ϕ B 0 ) and ideality factor ( n ) show strong temperature dependence. While n decreases, ϕ B 0 increases with increasing temperature. Experimental results show that the current across the SBDs may be greatly influenced by the existence of Schottky barrier height (SBH) inhomogeneity. These temperature behaviors have been explained on the basis of the thermionic emission (TE) theory with Gaussian distribution (GD) of the barrier heights (BHs) due to BH inhomogeneities at metal–semiconductor (M/S) interface. From this assumptions, obtaining Richardson constant value of the A * 121.01 A/cm 2 K 2 is perfect agreement with the theoretical value of 120 A/cm 2 K 2 for n-type Si. Hence, behaviors of the forward-bias I – V characteristics of the Au/TiO 2 /n-Si (SBDs) can be successfully explained on the basis of a TE mechanism with a double Gaussian distribution of the BHs.

Thermal annealing effects on I–V–T characteristics of sputtered Cr/n-GaAs diodes

Abstract Sputtered Cr/n - GaAs Schottky diodes have been prepared and annealed at 200 and 400 °C. The current–voltage ( I–V ) characteristics of the as-deposited and annealed diodes have been measured in the temperature range of 60–320 K with steps of 20 K. The effect of thermal annealing on the temperature-dependent I–V characteristics of the diodes has been investigated experimentally. The ideality factor and barrier height (BH) values for 400 °C annealed diode approximately remain unchanged from 120 to 320 K, and those of the as-deposited sample from 160 to 320 K. The departures from ideality at low temperatures have been ascribed to the lateral fluctuations of the BH. The BH values of 0.61 and 0.74 eV for the as-deposited and 400 °C annealed diodes were obtained at room temperature, respectively. A Richardson constant value of 9.83 A cm −2 K −2 for 400 °C annealed Schottky diode, which is in close agreement with the known value of 8.16 A cm −2 K −2 for n-type GaAs. Furthermore, T 0 anomaly values of 15.52, 10.68 and 5.35 for the as-deposited and 200 and 400 °C annealed diodes were obtained from the nT versus T plots. Thus, it has been seen that the interface structure and quality improve by the thermal annealing at 400 °C.

Examination by interfacial layer and inhomogeneous barrier height model of temperature-dependent I– V characteristics in Co/ p-InP contacts

The current–voltage ( I– V) characteristics of the sputtered Co/ p-InP Schottky diodes have been measured in the temperature range of 80–400 K with steps of 20 K. It has been seen that the I– V characteristics of the device cannot be explained by the classical thermionic emission theory due to the ideality factor values larger than unity, 2.01 at 300 K and 1.73 at 400 K which indicate the presence of a native oxide layer at the metal/semiconductor interface. Therefore, the I– V characteristics have been corrected for the effect of the native oxide layer with a transmission coefficient of θ p = 1.76 × 10 −3. The fact that the ideality factor and barrier height (BH) values have changed by change of the sample temperature has been attributed to the presence of the lateral inhomogeneities of the BH. Before correcting for the effect of the native oxide layer, the BH inhomogeneity has obeyed the double-Gaussian distribution (GD) model of BHs suggested in refs. [Y.L. Jiang, G.P. Ru, F. Lu, X.-P. Qu, B.Z. Li, W. Li, A.Z. Li, Chin. Phys. Lett. 19 (2002) 553; Y.L. Jiang, G.P. Ru, F. Lu, P.X. Qu, B.Z. Li, S. Young, J. Appl. Phys. 93 (2003) 866; S. Huang, F. Lu, Appl. Surf. Sci. 252 (2006) 4027] which assumes the simultaneous existence of two GDs of BHs. After correcting, the BH inhomogeneity has obeyed the single-GD model of BHs suggested by some authors, which fits to a straight line in the temperature range of 80–400 K. Thus, after correcting, a Richardson constant value of 76.45 A/cm 2 K 2, which is close agreement with the value of 60 A/cm 2 K 2 known for p-type InP, has been obtained from the modified ln( I 0C/ T 2) − q 2σ 2/(2 k 2 T 2) versus 1/ T plotted by the single-GD of the BHs.

Low-temperature thermionic emission from nitrogen-doped nanocrystalline diamond films on n-type Si grown by MPCVD

Temperature-dependent emission current–voltage measurements were carried out for nitrogen (N)-doped nanocrystalline diamond (NCD) films grown on n-type Si substrates by microwave plasma-assisted chemical vapor deposition (MP-CVD). Low threshold temperature (~ 260 °C) and low threshold electric field (~ 5 × 10 − 5 V/µm) were observed. Both the temperature dependence and the electric field dependence have shown that the obtained emission current was based on electron thermionic emission from N-doped NCD films. We have also studied the relation between nitrogen concentration and the saturation emission current. The saturation current obtained was as high as 1.4 mA at 5.6 × 10 − 3 V/µm at 670 °C when the nitrogen concentration was 2.4 × 10 20 cm − 3 . Low value of effective work function (1.99 eV) and relatively high value of Richardson constant (~ 70) were estimated by well fitting to Richardson–Dushman equation. The results of smaller φ and larger A′ suggest that N-doped NCD has great possibility of being a highly efficient thermionic emitter material.

The distribution of barrier heights in MIS type Schottky diodes from current–voltage–temperature ( I– V– T) measurements

The forward bias current–voltage–temperature ( I– V– T) characteristics of the Au/SiO 2/n-Si (MIS) type Schottky diodes (SDs) have been investigated in the temperature range of 300–400 K. The estimated zero-bias barrier height ( Φ B0) and the ideality factor ( n) assuming thermionic emission (TE) theory show strong temperature dependence. An abnormal decrease in the Φ B0 and an increase in the n with decreasing temperature have been explained on the basis of the TE theory with a Gaussian distribution (GD) of the barrier heights (BHs) due to BH inhomogeneities. The conventional Richardson plot should be a straight line especially at intermediate temperatures ( T ≤ 325). The values of activation energy ( E a) and Richardson constant ( A *) were determined as 0.167 eV and 1.385 × 10 −6 A cm −2 K −2 from the slope and the intercept at ordinate of the linear region of this plot, respectively. Also, we attempted to draw a Φ B0 versus q/2 kT plot in order to obtain evidence of the GD of BHs, and the values of Φ ¯ B0 = 1.301 eV and σ s = 0.187 V for the mean barrier height and zero-bias standard deviation have been obtained from this plot, respectively; then, a modified ln ( I 0 / T 2 ) − q 2 σ s 2 / 2 k 2 T 2 versus q/ kT plot gives Φ ¯ B0 and A * as 1.298 eV and 109.481 A cm −2 K −2, respectively. This value of the A * (=109.481 A cm −2 K −2) is very close to the theoretical value of 112 A cm −2 K −2 for n-type Si. Therefore, it has been concluded that the temperature dependence of the forward bias I– V characteristics of the MIS type Schottky diodes can be successfully explained on the basis of TE mechanism with a GD of the BHs.

Temperature-dependent Schottky barrier inhomogeneity of Ni/n-GaAs diodes

We have reported a study of the I – V characteristics of Ni/ n -GaAs Schottky barrier diodes (SBDs) in a wide temperature range of 60–320 K by a step of 20 K, which are prepared by magnetron DC sputtering. The experimental I – V data of the device quite well obey the thermionic emission model at 300 and 320 K, respectively. The ideality factor and barrier height values have changed by change of the sample temperature, the case has been attributed to the presence of the lateral inhomogeneities of the barrier height. The barrier inhomogeneity has been explained by the Gaussian distribution models of barrier heights suggested by some authors, Y.-L. Jiang et al. [Chin. Phys. Lett. 19 , 553 (2002)]; Y.-L. Jiang et al. [J. Appl. Phys. 93 , 866 (2003)], and S. Chand, J. Kumar [Appl. Phys. A 65 , 497 (1997)]. It has been seen that the SBH inhomogeneity of our Ni/n-GaAs SBD can be well described by Gaussian distribution model suggested by Y.-L. Jiang et al. [Chin. Phys. Lett. 19 , 553 (2002)]; Y.-L. Jiang et al. [J. Appl. Phys. 93 , 866 (2003)] over whole measurement temperature range. Moreover, the modified ln( $I_{0}/T ^{2}$ ) versus $1/k(T+T_0^\ast)$ plot is obtained using a method developed for T 0 anomaly in the literature. Richardson constant value of 3.37 A cm -2 K -2 for n -type GaAs was obtained from the modified Richardson plot.

Barrier characteristics of gold Schottky contacts on moderately doped n-InP based on temperature dependent I– V and C– V measurements

The temperature dependences of current–voltage ( I– V) and capacitance–voltage ( C– V) characteristics of the gold Schottky contacts on moderately doped n-InP (Au/MD n-InP) Schottky barrier diodes (SBDs) have been systematically investigated in the temperature range of 60–300 K. The main diode parameters, ideality factor ( n) and zero-bias barrier height (apparent barrier height) ( Φ b 0 j ) were found to be strongly temperature dependent and while the Φ b 0 j decreases, the n and the ( Φ b C ) increase with decreasing temperature. According to Thermionic Emission ( TE) theory, the slope of the conventional Richardson plot [ In( J 0/ T 2) vs. 1000/ T] should give the barrier height. However, the experimental data obtained do not correlate well with a straight line below 160 K. This behaviour has been interpreted on the basis of standard TE theory and the assumption of a Gaussian distribution of the barrier heights due to barrier inhomogeneities that persist at the metal-semiconductor interface. The linearity of the apparent barrier height ( Φ b 0 j ) vs. 1/(2 kT) plot that yields a mean barrier height ( Φ ¯ b 0 j ) of 0.526 eV and a standard deviation ( σ s0) of 0.06 eV, was interpreted as an evidence to apply the Gaussian distribution of the barrier height. Furthermore, modified Richardson plot [ In ( J 0 / T 2 ) - ( q 2 σ s 0 2 / 2 k 2 T 2 ) vs. 1/ T] has a good linearity over the investigated temperature range and gives the Φ ¯ b 0 j and the Richardson constant ( A ∗) values as 0.532 eV and 15.90 AK −2cm −2, respectively. The mean barrier heights obtained from both plots are appropriate with each other and the value of A ∗ obtained from the modified Richardson plot is close to the theoretical value of 9.4 AK −2cm −2 for n-InP. From the C– V characteristics, measured at 1 MHz, the capacitance was determined to increase with increasing temperature. C– V measurements have resulted in higher barrier heights than those obtained from I– V measurements. The discrepancy between Schottky barrier heights(SBHs) obtained from I– V and C– V measurements was also interpreted. As a result, it can be concluded that the temperature dependent characteristic parameters for Au/MD n-InP SBDs can be successfully explained on the basis of TE mechanism with Gaussian distribution of the barrier heights.

Current–voltage–temperature (I–V–T) characteristics of Pd/Au Schottky contacts on n-InP (1 1 1)

We have investigated the current–voltage–temperature (I–V–T) characteristics of Pd/Au/InP Schottky barrier diodes in the temperature range of 220–400K. The I–V analysis based on thermionic emission (TE) theory shows an abnormal decrease of apparent barrier height and increase of ideality factor at low temperatures. The conventional Richardson plot exhibits nonlinearity with activation energy of 0.17eV and the Richardson constant value of 5.63×10−6Acm−2K−2. The nonlinearity in the Richardson plot and strong dependence of Schottky barrier parameters on temperature may be attributed to the spatial inhomogeneity in the interface. Further, the homogeneous barrier height has been obtained from the linear relationship between experimentally obtained effective barrier heights and ideality factors. Φb versus (2kT)−1 plot has been drawn to obtain the mean barrier height [Φ¯bo(T=0K)] and the standard deviation (σs) at zero-bias which are found to be 0.84eV, 138meV, respectively. The series resistance is also estimated from the forward current–voltage characteristics of Pd/Au/InP Schottky contacts using Cheung’s method and found that it is strongly dependent on temperature and also decreases with increase in temperature.

The double Gaussian distribution of barrier heights in Al/TiO2/p-Si (metal-insulator-semiconductor) structures at low temperatures

The current-voltage (I-V) characteristics of Al/TiO2/p-Si metal-insulator-semiconductor (MIS) structures have been investigated in the temperature range of 80–300 K. An abnormal decrease in the zero bias barrier height (BH) (ϕb0) and an increase in the ideality factor (n) with decreasing temperature have been explained on the basis of the thermionic emission (TE) theory with Gaussian distribution (GD) of the BHs due to the BH inhomogeneities. The temperature dependence of the experimental I-V data of the Al/TiO2/p-Si (MIS) structures has revealed the existence of a double GD with mean BH values (ϕ¯b0) of 1.089 and 0.622 eV and standard deviations σs of 0.137 and 0.075 V, respectively. Thus, the modified ln(I0/T2)−q2σ02/2(kT)2 versus q/kT plot gives ϕ¯b0 values and Richardson constants (A∗) as 1.108 and 0.634 eV and 31.42 and 23.83 A/cm2 K2, respectively, without using the temperature coefficient of the BH. The value of the effective Richardson constant of 31.42 A/cm2 K2 is very close to the theoretical value of 32 A/cm2 K2 for p-Si. As a result, the temperature dependence of the forward bias I-V characteristics of the Al/TiO2/p-Si (MIS) structure can be successfully explained on the basis of the TE mechanism with a double GD of the BHs.

TEMPERATURE DEPENDENCE OF ELECTRICAL CHARACTERISTICS OF Cr/p–Si(100) SCHOTTKY BARRIER DIODES

The electrical characteristics of Cr / p – Si (100) Schottky barrier diodes have been measured in the temperature range of 100–300 K. The I-V analysis based on thermionic emission (TE) theory has revealed an abnormal decrease of apparent barrier height and increase of ideality factor at low temperature. The conventional Richardson plot exhibits non-linearity below 200 K with the linear portion corresponding to activation energy 0.304 eV and Richardson constant (A*) value of 5.41×10-3 Acm-2 K -2 is determined from the intercept at the ordinate of this experimental plot, which is much lower than the known value of 32 Acm-2 K -2 for p-type Si . It is demonstrated that these anomalies result due to the barrier height inhomogeneities prevailing at the metal-semiconductor interface. Hence, it has been concluded that the temperature dependence of the I-V characteristics of the Cr/p – Si Schottky barrier diode can be successfully explained on the basis of TE mechanism with a Gaussian distribution of the barrier heights. Furthermore, the value of the Richardson constant found is much closer than that obtained without considering the inhomogeneous barrier heights.

Electrical and photovoltaic properties of a n-Si/chitosan/Ag photodiode

The electrical and photovoltaic properties of AuSb/n-Si/chitosan/Ag diode have been investigated. The ideality factor, barrier height and Richardson constant values of the diode at room temperature were found to be 1.91, 0.88 eV and 121.4 A/cm 2 K 2, respectively. The ideality factor of the diode is higher than unity, suggesting that the diode shows a non-ideal behaviour due to series resistance and barrier height inhomogeneities. The barrier height and ideality factor values of Ag/CHT/n-Si diode at room temperature are significantly larger than that of the conventional Ag/n-Si Schottky diode. The φ B value obtained from C– V measurement is higher than that of φ B value obtained from I– V measurement. The discrepancy between φ B( C– V) and φ B( I– V) barrier height values can be explained by Schottky barrier height inhomogeneities. AuSb/n-Si/chitosan/Ag diode indicates a photovoltaic behaviour with open circuit voltage ( V oc = 0.23 V) and short-circuit current density ( J sc = 0.10 μA/cm −2) values.

Temperature-dependent current–voltage and capacitance–voltage characteristics of the Ag/n-InP/In Schottky diodes

The current–voltage (I–V) and capacitance–voltage (C–V) characteristics of Ag/n-InP/In Schottky diodes have been studied in a wide temperature range by steps of 10 K. A decrease in the apparent barrier height (BH), \(\Upphi_{bo}\), an increase in the ideality factor, \(n\) and a nonlinearity in the activation energy plot with a decrease in temperature have been seen. The experimental values of BH and ideality factor for the devices were calculated as 0.61 eV and 1.18 at 320 K, 0.48 eV and 1.52 at 200 K, and 0.20 eV and 3.89 at 70 K, respectively. An abnormal decrease in the experimental BH \(\Upphi_{b}\) and an increase in the ideality factor n with a decrease in temperature have been explained by the barrier inhomogeneities at the metal–semiconductor (MS) interface. From the temperature dependent I–V characteristics of the Ag/n-InP contact, that is, \(\overline{\Upphi}_{bo}\) and A* as 0.79 and 0.55 eV, and 7.96 and \(8.18\,\hbox{A/cm}^{2}\hbox{K}^{2}\), respectively, have been calculated from a modified \(\hbox{ln}(I_{0}/T^{2})-q^{2}\sigma _s^2/2k^{2}T^{2}\) vs. 1/T plot for the two temperature regions. The Richardson constant values are in close agreement with the value of \(9.8\,\hbox{A/cm}^{2}\hbox{K}^{2}\) known for n-type InP. Moreover, the difference between the apparent BHs obtained from the I–V and C–V characteristics has been attributed to the existence of Schottky BH inhomogeneity.

The distribution of the barrier height in Al–TiW–Pd2Si/n-Si Schottky diodes from I–V–T measurements

The forward and reverse bias current–voltage (I–V) characteristics of Al–TiW–Pd2Si/n-Si Schottky barrier diodes (SBDs) were measured in the temperature range of 300–400 K. The estimated zero-bias barrier height ΦB0 and the ideality factor n assuming thermionic emission (TE) theory show a strong temperature dependence. While n decreases, ΦB0 increases with increasing temperature. The Richardson plot is found to be linear in the temperature range measured, but the activation energy value of 0.378 eV and the Richardson constant (A*) value of 15.51 A cm−2 K−2 obtained in this plot are much lower than the known values. Such behavior is attributed to Schottky barrier inhomogeneities by assuming a Gaussian distribution of barrier heights (BHs) due to BH inhomogeneities that prevail at the interface. Also, the ΦB0 versus q/2kT plot was drawn to obtain evidence of a Gaussian distribution of the BHs, and ΦB0 = 0.535 eV and σ0 = 0.069 V for the mean BH and zero-bias standard deviation, respectively, have been obtained from this plot. Thus, the modified ln(I0/T2) − q2σ20/2k2T2 versus q/kT plot gives ΦB0 and A* as 0.510 eV and 121.96 A cm−2 K−2, respectively. This value of the Richardson constant 121.96 A cm−2 K−2 is very close to the theoretical value of 120 A K−2 cm−2 for n-type Si. Hence, it has been concluded that the temperature dependence of the forward I–V characteristics of the Al–TiW–Pd2Si/n-Si Schottky barrier diodes can be successfully explained on the basis of a thermionic emission mechanism with a Gaussian distribution of the BHs.

Barrier inhomogeneities in Au/CdSe thin film Schottky diodes

Schottky diodes have been fabricated by depositing Au on n-type CdSe thin films using the thermal evaporation technique, and their properties have been investigated by current–voltage and capacitance–voltage measurements. At room temperature, the characteristics obey the pure thermionic emission theory and the barrier height has been found to be 0.63 eV. The barrier heights decrease, while ideality factors increase with decrease in temperature. Further, the activation energy plot does not provide the expected Richardson constant and barrier height values. The abnormal behavior of the barrier heights and the ideality factors with respect to temperature as well as the difference between the barrier heights measured from I–V and those from C–V or flat band have been explored on the basis of barrier height inhomogeneities.

The behavior of the I-V-T characteristics of inhomogeneous (Ni∕Au)–Al0.3Ga0.7N∕AlN∕GaN heterostructures at high temperatures

We investigated the behavior of the forward bias current-voltage-temperature (I-V-T) characteristics of inhomogeneous (Ni∕Au)–Al0.3Ga0.7N∕AlN∕GaN heterostructures in the temperature range of 295–415K. The experimental results show that all forward bias semilogarithmic I-V curves for the different temperatures have a nearly common cross point at a certain bias voltage, even with finite series resistance. At this cross point, the sample current is temperature independent. We also found that the values of series resistance (Rs) that were obtained from Cheung’s method are strongly dependent on temperature and the values abnormally increased with increasing temperature. Moreover, the ideality factor (n), zero-bias barrier height (ΦB0) obtained from I-V curves, and Rs were found to be strongly temperature dependent and while ΦB0 increases, n decreases with increasing temperature. Such behavior of ΦB0 and n is attributed to Schottky barrier inhomogeneities by assuming a Gaussian distribution (GD) of the barrier heights (BHs) at the metal∕semiconductor interface. We attempted to draw a ΦB0 versus q∕2kT plot in order to obtain evidence of the GD of BHs, and the values of Φ¯B0=1.63eV and σ0=0.217V for the mean barrier height and standard deviation at a zero bias, respectively, were obtained from this plot. Therefore, a modified ln(I0∕T2)−q2σ02∕2(kT)2 versus q∕kT plot gives ΦB0 and Richardson constant A* as 1.64eV and 34.25A∕cm2K2, respectively, without using the temperature coefficient of the barrier height. The Richardson constant value of 34.25A∕cm2K2 is very close to the theoretical value of 33.74A∕cm2K2 for undoped Al0,3Ga0,7N. Therefore, it has been concluded that the temperature dependence of the forward I-V characteristics of the (Ni∕Au)–Al0.3Ga0.7∕AlN∕GaN heterostructures can be successfully explained based on the thermionic emission mechanism with the GD of BHs.

Temperature-dependent behavior of Ni/4H-nSiC Schottky contacts

The current-voltage (I-V) characteristics of Ni/4H-nSiC Schottky diodes have been measured in the temperature range of 180–300 K with a temperature step of 20 K. An experimental barrier height (BH) Φap value of about 1.32 eV was obtained for the Ni/4H-nSiC Schottky diode at the 300 K. A decrease in the experimental BH Φap and an increase in the ideality factor n with a decrease in temperature have been explained on the basis of a thermionic emission mechanism with Gaussian distribution of the barrier heights due to the BH inhomogeneities at the metal-semiconductor interface. Φ¯b and A* as 1.71 eV, and 156.3 A/cm2 K2, respectively, have been calculated from a modified ln(I0/T2)−q2σs2/2k2T2 vs 1/T plot using the temperature-dependent experimental I-V characteristics of the Ni/4H-nSiC contact. The Richardson constant value of 156.3 A/cm2 K2 is in close agreement with 146 A/cm2 K2 known for 4H-nSiC.

Ferroelectric polarization-leakage current relation in high quality epitaxialPb(Zr,Ti)O3films

Leakage current measurements were performed on epitaxial, single-crystal quality $\mathrm{Pb}(\mathrm{Zr},\mathrm{Ti}){\mathrm{O}}_{3}$ films with thicknesses in the $50--300\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ range. It was found that the voltage behavior of the leakage current has a minor dependence on thickness, which rules out the space-charge limited currents as main leakage source. Temperature-dependent measurements were performed to obtain more information on the transport mechanism through the metal-ferroelectric-metal (MFM) structure. The results are analyzed in the frame of interface-controlled Schottky emission. A surprisingly low value of only $0.12--0.13\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ was obtained for the potential barrier, which is much smaller than the reported value of $0.87\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ [I. Stolichnov et al., Appl. Phys. Lett. 75, 1790 (1999)]. The result is explained by the effect of the ferroelectric polarization on the potential barrier height. The low value of the effective Richardson constant, of the order of ${10}^{\ensuremath{-}7}--{10}^{\ensuremath{-}6}\phantom{\rule{0.3em}{0ex}}\mathrm{A}∕{\mathrm{cm}}^{2}\phantom{\rule{0.2em}{0ex}}{\mathrm{K}}^{2}$, suggests that the pure thermionic emission is not the adequate conduction mechanism for epitaxial MFM structures. The true mechanism might be interface-controlled injection, followed by a low mobility drift through the film volume.

Temperature-dependent optical absorption measurements and Schottky contact behavior in layered semiconductor n-type InSe(:Sn)

The layered n-InSe(:Sn) single crystal samples have been cleaved from a large crystal ingot grown from non-stoichiometric melt by the Bridgman–Stockbarger method. It has been made the absorption measurements of these samples without Schottky contact under electric fields of 0.0 and 6000 V cm −1. The band gap energy value of the InSe:Sn has been calculated as 1.36 ± 0.01 eV (at 10 K) and 1.28 ± 0.01 eV (at 300 K) under zero electrical field, and 1.31 ± 0.01 eV (at 10 K) and 1.26 ± 0.01 eV (at 300 K) under 6000 Vcm −1. The current–voltage ( I– V) characteristics of Au–Ge/InSe(:Sn)/In Schottky diodes have been measured in the temperature range 80–320 K with a temperature step of 20 K. An experimental barrier height (BH) Φ ap value of about 0.70 ± 0.01 eV was obtained for the Au–Ge/InSe(:Sn)/In Schottky diode at the room temperature (300 K). An abnormal decrease in the experimental BH Φ b and an increase in the ideality factor n with a decrease in temperature have been explained by the barrier inhomogeneities at the metal–semiconductor interface. From the temperature-dependent I– V characteristics of the Au–Ge/InSe(:Sn)/In contact, that is, Φ ¯ bo and A * as 0.94 ± 0.02 and 0.58 ± 0.02 eV, and 27 ± 2 and 21 ± 1 (A/cm 2 K 2), respectively, have been calculated from a modified ln ( I 0 / T 2 ) − q 2 σ s 2 / 2 k 2 T 2 versus 1/ T plot for the two temperature regions. The Richardson constant values are about two times larger than the known value of 14.4 (A/cm 2 K 2) known for n-type InSe. Moreover, in the temperature range 80–320 K, we have also discussed whether or not the current through the junction has been connected with TFE.

Temperature dependence of electrical parameters of the Au/n-InP Schottky barrier diodes

The temperature dependence of current–voltage (I–V) and capacitance–voltage (C–V) characteristics of the Au/n-InP Schottky barrier diodes has been measured in the temperature range of 80–320 K. The forward I–V characteristics are analysed on the basis of standard thermionic emission (TE) theory and the assumption of a Gaussian distribution of the barrier heights (BHs). It has been shown that the ideality factor decreases while the barrier height increases with increasing temperatures, on the basis of TE theory. Furthermore, the homogeneous BH value of approximately 0.524 eV for the device has been obtained from the linear relationship between the temperature-dependent experimentally effective BHs and ideality factors. The modified Richardson plot, according to inhomogeneity of the BHs, has a good linearity over the temperature range. The value of Richardson constant A* has been found to be 5.97 A cm−2 K−2, which is close to the theoretical value of 9.4 A cm−2 K−2 for n-InP. Moreover, the temperature coefficient of the BH is found to be −3.16 × 10−4 eV K−1 for Au/n-InP.

Temperature-Dependent Barrier Characteristics of InhomogeneousIn/p-Si (100) Schottky Barrier Diodes

The current-voltage (I–V) characteristics of In/p-Si Schottkybarrier diodes have been determined in the temperature range 100–300 Kand have been interpreted based on the assumption of a Gaussiandistribution of barrier heights due to barrier height inhomogeneitiesthat prevail at the metal–semiconductor interface. The evaluation ofthe experimental I–V data reveals a decrease of zero-biasbarrier height but an increase of ideality factor n with decreasingtemperature. The inhomogeneities are considered to have Gaussiandistribution with a mean zero-bias barrier height of 0.630 eV andstandard deviation of 0.083 V at zero bias. Furthermore, the meanbarrier height and the Richardson constant values were obtained to be0.617 eV and 20.71 A K−2 cm−2, respectively, by means ofthe modified Richardson plot, ln (I0/T2)−(q2σs02/2k2T2) versus 1000/T.