Gaussian Height Distribution Research Articles

The synthesis of 4,4′-(9,9-dioctyl-9H-fluorene-2,7-diyl)bis(N,N-diphenylaniline) organic semiconductor and use of it as an interlayer on Au/n-Si diode

In the present study, firstly, a 4,4′-(9,9-dioctyl-9H-fluorene-2,7-diyl)bis(N,N-diphenylaniline) (FC) organic compound was synthesized and its structural and optical characterization were carried. Then, the effect on the device of the FC thin film prepared between n-type silicon substrate and gold metal by the spin coating technique was reported. The ideality factor (n), barrier height ( $$ \Phi_{B} $$ ) and series resistance ( $$ R_{s} $$ ) values of the prepared structure from the I-V data have been found at 1.08, 0.78 eV and 240 Ω at room temperature (300 K), respectively. According to the Gaussian distribution of the barrier height obtained from the various temperature ranges (220–380 K), the $$ \Phi_{b0} $$ and A* values from the ordinate intercept and the slope of the modified Richardson curve of $$ \ln \left( {I_{0} /T^{2} } \right) - \left( {q^{2} \sigma_{s}^{2} /2k^{2} T^{2} } \right) $$ versus 1/T plot which has been found to be 0.97 eV and 114 A/cm2K2, respectively. Results indicate that the high barrier height is achieved for the Au/FC/n-Si metal–organic layer-semiconductor diode as compared to the Au/n-Si metal–semiconductor (MS) diode.

Evaluation of temperature dependent electrical transport parameters in Fe3O4/SiO2/n-Si metal–insulator-semiconductor (MIS) type Schottky barrier heterojunction in a wide temperature range

In this manuscript, we reported the electrical characteristics and structural analysis of In/Fe3O4/SiO2/n-Si/In MIS-type SBD heterostructure comprehensively in the temperature range 10–300 K using I–V, XRD, TEM and AFM measurements. Pulsed laser deposition in association with DC magnetron sputtering techniques has been utilized to fabricate the proposed In/Fe3O4/SiO2/n-Si/In heterojunction. The fabricated heterojunction revealed that the I–V curves are non-linear and asymmetric in nature. Using these I–V curves in the forward-bias region, SBH is calculated as 0.02 eV at 10 K and 0.74 eV at 300 K. On the other hand, the ideality factor (n) value was calculated as 7.55 at 10 K and 1.37 at 300 K. The series resistance (RS) values were also evaluated using Chenug’s method and the values were 1121 Ω at 10 K and 334 Ω at 300 K. The dependence of important diode parameters such as SBH, ‘n’ and ‘RS’ on measurement temperature was effectively explained firstly on account of triple Gaussian distribution of barrier heights with the help of barrier inhomogeneities of the prepared heterojunction. The value of the Richardson’s constant calculated for the fabricated In/Fe3O4/SiO2/n-Si/In heterojunction in the 110–300 K temperature regime was calculated to be 115.26 A/cm2K2 and is approximately equal to the theoretical value of 120 A/cm2K2 for n-type Si. In addition, the higher value (greater than one) of ideality factor at all operating temperatures from 10–300 K demonstrated that the probable current transport across the Fe3O4/SiO2/n-Si junction is not only due to the thermionic emission (TE) mechanism. Hence, to reveal the origin of current transport mechanism i.e., other than TE, we noticed that the governing current transport process through the fabricated hetrojunction is mainly due to the tunneling assisted Poole–Frenkel class of emission across the Fe3O4/SiO2/n-Si junction which is found to be temperature-dependent.

On the possible conduction mechanisms in Rhenium/n-GaAs Schottky barrier diodes fabricated by pulsed laser deposition in temperature range of 60–400 K

This study presents electrical characteristics of n-GaAs based Schottky barrier diodes (SBDs) with Rhenium (Re) rectifier contacts. The electrical characteristics of the Re/n-GaAs SBDs were investigated utilizing the forward bias current–voltage (IF–VF) data collected in temperature range of 60–400 K. The values of ideality factor (n) and zero-bias barrier height (ΦBo) were found as 9.10 and 0.11 eV for 60 K, and 1.384 and 0.624 eV for 400 K, respectively, on the basis of thermionic-emission theory. The conventional Richardson plot deviated from linearity at low temperatures and the Richardson constant value (A*) was obtained quite lower than the theoretical value for this semiconductor (8.16 A cm−2 K−2). nkT/q–kT/q plot shows that the field-emission may be dominant mechanism at low temperatures as a result of tunneling via surface states since the studied n-GaAs’s doping concentration is on the order of 1018 cm−3, i.e. at high values so leads to tunneling. On the other hand, ΦBo–n, ΦBo–q/2kT and (n−1 − 1)–q/2kT plots exhibit linearity but this linearity is observed for two temperature regions (60–160 K and 180–400 K) due the presence of double Gaussian distribution (GD) of the barrier height. Therefore, the standard deviation value was obtained from the plot of ΦBo–q/2kT and it was used for modifying the conventional Richardson plot into the modified Richardson plot by which the values of mean barrier height and A* were obtained as 0.386 eV and 15.55 A cm−2 K−2 and 0.878 eV and 8.35 A cm−2 K−2 for the low and high temperature regions, respectively. As a result, IF–VF–T characteristics of the Re/n-GaAs SBDs were successfully elucidated by double-GD of barrier height.

Junction properties of single ZnO nanowires with asymmetrical Pt and Cu contacts

Metal–semiconductor interfaces play a crucial role not only for regulating the electronic conduction mechanism but also in determining new functionalities in nanosized devices. In this work, we reported the investigation of the junction properties of single ZnO nanowires (NWs) asymmetrically contacted by means of a Pt electrochemically inert and a Cu electrochemically active electrode. At low applied voltages, these devices operate as diodes where the conduction mechanism was found to be dominated by the Schottky barrier at the Cu/ZnO interface. Junction parameters such as the Schottky barrier height, the ideality factor and the series resistance have been analyzed according to the thermionic emission theory. Different methods for parameter retrieval from I–V–T measurements are discussed and compared. A potential fluctuation model is considered in order to account for barrier inhomogeneities, revealing the presence of two Gaussian distribution of barrier heights. On the other hand, new device features arise from electrochemical dissolution and migration of Cu ions along the NW when high electric fields are implied. These electrochemical processes are underlaying the resistive switching and memristive behavior observed in single ZnO NWs, as suggested also by direct observation of Cu nanoclusters along the nanostructures after the switching events.

Temperature dependence of electrical properties in $$\hbox {In/Cu}_{{2}}\hbox {ZnSnTe}_{{4}}\hbox {/Si/Ag diodes}$$ In/Cu 2 ZnSnTe 4 /Si/Ag diodes

\(\hbox {Cu}_{{2}}\hbox {ZnSnTe}_{4}\) (CZTTe) thin films with In metal contact were deposited by thermal evaporation on monocrystalline n-type Si wafers with Ag ohmic contact to investigate the device characteristics of an In/CZTTe/Si/Ag diode. The variation in electrical characteristics of the diode was analysed by carrying out current–voltage (I–V) measurements in the temperature range of 220–360 K. The forward bias I–V behaviour was modelled according to the thermionic emission (TE) theory to obtain main diode parameters. In addition, the experimental data were detailed by taking into account the presence of an interfacial layer and possible dominant current transport mechanisms were studied under analysis of ideality factor, n. Strong effects of temperature were observed on zero-bias barrier height \((\Phi _{\mathrm{B}0} )\) and n values due to barrier height inhomogeneity at the interface. The anomaly observed in the analysis of TE was modelled by Gaussian distribution (GD) of barrier heights with 0.844 eV mean barrier height and 0.132 V standard deviation. According to the Tung’s theoretical approach, a linear correlation between \(\Phi _{\mathrm{B}0} \) and n cannot be satisfied, and thus the modified Richardson plot was used to determine Richardson constant \((A^{*})\). As a result, \(A^{*}\) was calculated approximately as \(120.6\hbox { A cm}^{-2}~\hbox {K}^{-2}\) very close to the theoretical value for n-Si. In addition, the effects of series resistance \((R_{\mathrm{s}} )\) by estimating from Cheng’s function and density of surface states \((N_{\mathrm{ss}} )\) by taking the bias dependence of effective barrier height, were discussed.

A vertical optimization method for a simultaneous extraction of the five parameters characterizing the barrier height in the Mo/4H–SiC Schottky contact

The temperature dependence of the parameters related to the barrier height inhomogeneities for Mo/4H–SiC Schottky diode in 298–498 K temperature range has been investigated. Due to the barrier height inhomogeneities that prevail at the interface of the Schottky diode, a Gaussian distribution of the barrier height is assumed. We have extracted simultaneously, for every temperature, all the parameters characterizing the barrier height such as the mean barrier height $$ \bar{\phi }_{{{\text{B}}0}} $$ , the coefficients ρ2, ρ3 quantifying the deformation of the barrier height, the corresponding temperature T0 modeling the divergence of the ideality factor n from the unity, the standard deviation of the Gaussian distribution of the barrier σs and also the series resistance Rs using a vertical optimization process on the current without any graphical extraction about ρ2, ρ3, $$ \bar{\phi }_{{{\text{B}}0}} $$ , σs and Rs. The extracted parameters like ( $$ \bar{\phi }_{{{\text{B}}0}} $$ , ρ2, ρ3, σs, Rs) were found to be a temperature dependent. Moreover, an excellent agreement was obtained between the I–V–T plots calculated with the extracted parameters using a vertical optimization process with the experimental one.

STATISTICAL DISTRIBUTION OF THE LAYERED ROUGH SURFACE INDEX (LRSI)

In this paper we determine the statistical distributions of the co-and cross-polarized Layered Rough Surface Index (LRSI) for three-dimensional layered structures with an arbitrary number of slightly rough interfaces illuminated by an electromagnetic plane wave. For infinite surface areas and Gaussian centered height distributions, we show within the framework of the first-order small perturbation method that the LRSI under a given observation direction is a random variable, whose statistical distribution is only function of two parameters. Contrary to the intensity ratio which follows a heavy-tailed distribution, the LRSI has finite mean and variance. For a structure air/clayey soil/rock, we analyze the influence of a snow layer upon the probability laws in the cases of Gaussian or exponential correlation functions.

Measure and analysis of 4H-SiC Schottky barrier height with Mo contacts

Current–voltage (I–V) and capacitance–voltage (C–V) characteristics of Schottky Mo/4H-SiC diodes have been measured and analyzed as a function of temperature between 80 and 400 K. The I–V characteristics significantly deviate from ideal characteristics predicted by the thermionic emission model because of the inhomogeneity of Schottky contact. After a brief review of the different existing models, the main parameters (ideality factor, barrier height, and effective Richardson constant) of both diodes have been extracted in the frame of a Gaussian barrier height distribution model, whose mean and standard deviation are linearly dependent on voltage and temperature, as well as in the context of the potential fluctuation model. The results are compared with the values extracted by C–V and the values in the literature. A link is established between these two models. Diodes of different I–V characteristics, either identified as single barrier or double barrier, have been analyzed by Deep Level Transient Spectroscopy (DLTS) to investigate the deep level defects present. No noticeable difference has been found.

Gaussian distribution in current-conduction mechanism of (Ni/Pt) Schottky contacts on wide bandgap AlInGaN quaternary alloy

The current-conduction mechanisms of the as-deposited and annealed at 450 °C (Ni/Pt) Schottky contacts on AlInGaN quaternary alloy have been investigated in the temperature range of 80–320 K. The zero-bias barrier height (BH) (ΦB0) and ideality factor (n) of them were evaluated using thermionic emission (TE) theory. The ΦB0 and n values calculated from the I-V characteristics show a strong temperature dependence. Such behavior of ΦB0 and n is attributed to Schottky barrier inhomogeneities. Therefore, both the ΦB0 vs n and ΦB0 vs q/2kT plots were drawn to obtain evidence on the Gaussian distribution (GD) of the barrier height at the metal/semiconductor interface. These plots show two different linear parts at low and intermediate temperatures for as-deposited and annealed Schottky contacts. Thus, the mean value of ΦB0 and standard deviation (σ0) was calculated from the linear parts of the ΦB0 vs q/kT plots for both samples. The values of the effective Richardson constant (A∗) and mean BH were obtained from the modified Richardson plots which included the effect of barrier inhomogeneity. These values of Richardson constant and barrier height for as-deposited contacts were found to be 19.9 A cm−2 K−2 and 0.59 eV, respectively, at low temperature, but 43.3 A cm−2 K−2 and 1.32 eV, respectively, at intermediate temperatures. These values of Richardson constant and barrier height for annealed contacts were found to be 19.6 A cm−2 K−2 and 0.37 eV, respectively, at low temperature, but 42.9 A cm−2 K−2 and 1.54 eV, respectively, at intermediate temperatures. It is clear that the value of the Richardson constant obtained for as-deposited and annealed samples by using double-GD for intermediate temperatures is close to the theoretical value of AlInGaN (=44.7 A cm−2 K−2). Therefore, I-V-T characteristics for the as-deposited and annealed Schottky contacts in the temperature range of 80–320 K can be successfully explained based on TE theory with double-GD of the BHs.

Effect of indium doping on the electrical and structural properties of TiO2 thin films used in MOS devices

We investigated the effect of Indium (In) doping on the structural and electrical properties of Ti/Au/TiO2:In/n-Si metal-oxide-semiconductor (MOS) devices. Sputtering grown TiO2 thin films on Si substrate were doped using two In-films with 15 nm and 50 nm thicknesses leading to two structures named Low Indium Doped (LID) sample and High Indium Doped (HID) sample, respectively. XRD analysis shows no diffraction pattern related to Indium indicating that In has been incorporated into the TiO2 lattice. Current-Voltage (I-V) characteristics show that rectification ratio at 2 V is higher for HID sample than for LID sample. Evaluated barrier height, ϕB0, decreased while the ideality factor, n, increased with decreasing temperature. Such behavior is ascribed to barrier inhomogeneity that was assumed to have a Gaussian Distribution (GD) of barrier heights at interface. Evidence of such GD was confirmed by plotting ϕB0 versus n. High value of mean barrier ϕ¯B0 and lower value of standard deviation (σ) of HID structure are due to indium doping which increases the barrier homogeneities. Finally, estimated Richardson constants A* are in good agreement with theoretic values (112 A/cm2K2), particularly, for the HID structure.

The co- and cross-polarized scattered intensity ratios for 3D layered structures with randomly rough interfaces

We determine the statistical distributions for the co- and cross-polarized scattered intensity ratios characterizing three-dimensional layered structures with an arbitrary number of rough interfaces illuminated by a plane wave. Within the framework of the first-order small perturbation method, we show for slightly rough interfaces with infinite surface areas and Gaussian height distributions that the intensity ratio is a random variable, the probability law of which is a function of two parameters. For air/clayey soil/rock structures, we analyze the influence of a snow layer upon the probability laws and we validate the closed-form formulae by comparison with Monte-Carlo simulations.

Current-Transport Mechanisms of the Al/(Bi2S3-PVA Nanocomposite)/p-Si Schottky Diodes in the Temperature Range Between 220 K and 380 K

In this research, bismuth sulfide nanostructures were prepared in the presence of polyvinyl alcohol (PVA) as a capping agent by an ultrasound-assisted method. The x-ray diffraction results show the crystalline phase of the sample and the mean crystalline size estimated by Debye–Scherer’s equation. The UV–Vis absorption spectrum show that the optical absorbance edge of Bi2S3 nanostructure was blue-shifted. The Fourier transform infrared spectra confirm the presence of PVA in the sample and transmission electron microscopy imaging shows that the structures are in nanoscale. The semi-logarithmic forward bias I–V plots have two distinct linear regimes for each temperature which are called low- and moderate-bias regions (LBR and MBR). In order to effectively interpret possible current-conduction/transport mechanisms, the reverse saturation current (Io), ideality factor (n) and zero-bias barrier height (ΦBO) were obtained from the slope and intercept of these plots and they were found to be a strong function of temperature and voltage. The high value of n even at high temperature and the increase of ΦBO with increasing temperature for the two regions is clear evidence of the deviation from thermionic emission (TE) theory. Therefore, ΦBO versus n and q/2kT plots were drawn to get evidence of the Gaussian distribution (GD) of the barrier height (BH) and they show a linear behavior. The mean values of BH ( $$ \bar{\Phi }_{\rm{BO}} $$ ) and standard deviation (σs) were also obtained from the intercepts and slopes of the ΦBO versus q/2kT plots as 1.44 eV and 0.19 V for the LBR and 1.32 eV and 0.18 V for the MBR, respectively. After that, the values $$ \bar{\Phi }_{\rm{BO}} $$ and effective Richardson constant (A*) were obtained as 1.29 eV and 267.6 A/(cm K)2 for the LBR and 1.27 eV and 281.7 A/(cm K)2 for the MBR, respectively. Such non-ideal I–V–T characteristics for the Al/(PVA-Bi2S3)/p-Si structure can be successfully explained by the single GD of BH for the LBR and MBR.

Electrical properties of Au–Cu/ZnO/p-Si diode fabricated by atomic layer deposition

The electrical properties of the Au–Cu/ZnO/p-Si diode were investigated with the temperature dependent current–voltage measurements in a wide temperature range from 220 to 360 K with 20 K steps and also frequency dependent capacitance–voltage and conductance–voltage measurements using admittance spectroscopy by changing frequency from 1 to 1000 kHz. The ZnO thin film layer was deposited by atomic layer deposition technique (ALD) to obtain homogenous interface layer and this layer surface was characterized with AFM analyses. Assuming thermionic emission (TE) model, diode parameters such as barrier height and ideality factor were determined for the Au–Cu/ZnO/p-Si diodes and the strong temperature dependence of these values were modeled by TE model with modified by Gaussian distribution of the barrier height. Therefore, the observed non-ideal current behavior was discussed on the basis of barrier inhomogeneity and the presence of native oxide interfacial layer in the diode. The mean barrier height was found as 1.38 eV with 0.18 standard deviation, and the Richardson constant modified by this model was obtained as 28 A/cm2k2 close to the theoretical value. Additionally, the distribution profile of the interface states and series resistance value were evaluated by the capacitance and conductance characteristics. It could be seen from the results that both of them strongly depends on the device frequency. As a result of these works, fabricated Au–Cu/ZnO/p-Si diodes may be used for next technological application in wide range temperature in industry.

Analysis of barrier inhomogeneities in AuGe/n-Ge Schottky diode

The barrier inhomogeneities in AuGe/n-Ge Schottky diode have been analyzed by using current–voltage (I–V) measurements over a wide temperature range of 200 to 400 K. The electrical parameters such as ideality factor (n), zero-bias barrier height (ΦBo), and series resistance (Rs) of the diode were found to be strongly temperature dependent. The abnormal increase of the barrier height with temperature was attributed to the existence of barrier height inhomogeneities at the metal/semiconductor interface. Therefore, the conventional and modified Richardson plots were drawn to explain Gaussian distribution (GD) of barrier heights. The modified Richardson plot shows a good linearity over the temperature range. The modified Richardson constant (A*) was found to be 141.49 A cm−2 K−2, which is close to the theoretical value of 140 A cm−2 K−2 for n-Ge. Moreover, the barrier height values obtained from I–V and Norde methods are found to be in good agreement with each other.

Investigation of carrier transport mechanisms in the Cu–Zn–Se based hetero-structure grown by sputtering technique

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.

The investigation of current-conduction mechanisms (CCMs) in Au/ (0.07Zn-PVA)/n-4H-SiC (MPS) Schottky diodes (SDs) by using (I-V-T) measurements

The semi-logarithmic forward bias I-V plots of the Au/(0.07Zn-PVA)/n-4H-SiC (MPS) type SBDs showed double exponential behavior therefore these plots revealed two distinct linear regions which correspond to low (0.05 V ≤ 0.4 V) and moderate voltage regions (0.4 ≤ V ≤ 0.8 V) (LBR and MBR), respectively, for each temperature level. It was observed that the value of ideality factor (n) decreased with increasing temperature whereas opposite behavior occurred for zero-bias barrier height (ΦB0). The behavior of nkT/q vs kT/q plot for MBR indicated that a combination of thermionic field emission (TFE) and field emission (FE) mechanisms, i.e. the tunneling mechanism, may be dominant especially at low temperatures. In order to explain such unexpected behavior of the conduction mechanism; ΦB0 vs n, ΦB0 vs q/2kT and (n−1 − 1) vs q/2kT plots were drawn to obtain an evidence of a Gaussian distribution (GD) of the barrier heights (BHs) and all of them revealed two linear regions for both LBR and MBR. The conventional Richardson plot was modified by using the obtained standard deviation (σso) of BH from ΦB0 vs q/2kT plots for two bias regions. Thus, the mean BH (Φ̅B0) and effective Richardson constant (A*) values for LBR were calculated from the slope and intercept of the modified Richardson plots as 0.730 eV, 114.12 A cm−2 K−2 at low temperature range (100 ≤ T ≤ 200 K) and 1.304 eV, 97.33 A cm−2 K−2 at high temperature range (200 ≤ T ≤ 320 K), respectively. These values for MBR were found as 0.687 eV, 144.97 A cm−2 K−2 at low temperature range and 1.165 eV, 122.11 A cm−2 K−2 at high temperature range, respectively. It is clear that the values of A* for MBR at low temperatures are closer to 146 A cm−2 K−2 which represents the theoretical value of for n-4H-SiC. As a result, the current conduction mechanisms (CCM) in Au/(0.07Zn-PVA)/n-4H-SiC (MPS) SD can be successfully explained by thermionic emission (TE) mechanism with the double GD of BHs.

Double Gaussian barrier distribution of permalloy (Ni0.8Fe0.2) Schottky contacts to n-type GaN

The temperature-dependent current-voltage (I-V) characteristics of permalloy (Ni0.8Fe0.2) Schottky contacts to n-type GaN have been investigated. Magnetization measurements revealed the ferromagnetic behavior of Ni0.8Fe0.2 film on n-type GaN. The Schottky barrier parameters, such as the barrier height and ideality factor, determined by thermionic emission depended on the measurement temperature, suggesting the presence of lateral inhomogeneity in the Schottky barrier. The experimental data modified by the thermionic emission model along with a Gaussian distribution of the barrier heights indicated the presence of a double Gaussian barrier distribution in the Ni0.8Fe0.2/n-type GaN Schottky contact. The mean barrier heights and standard deviations for each Gaussian distribution were 0.84 & 1.32 eV and 0.10 & 0.17 eV over temperature range of 125–200 K and 225–400 K, respectively. The noise spectral density of the current fluctuations measured as a function of frequency (f) at room temperature followed a 1/fγ dependence with a γ value close to unity, irrespective of the applied forward bias. The 1/f-type noise was attributed to the barrier inhomogeneity existing at the Ni0.8Fe0.2/n-type GaN Schottky interface as revealed from the temperature-dependent I–V characteristics.

A study of temperature dependent current–voltage (I–V–T) characteristics in Ni/sol–gel β-Ga2O3/n-GaN structure

β-Ga2O3 thin films were grown on n-type GaN substrates using the sol–gel method. The forward-biased temperature dependent current–voltage (I–V–T) characteristics of Ni/β-Ga2O3/GaN structure have been investigated in the temperature range of 298–473 K. The apparent barrier height ( $${\phi _{ap}}$$ ) increased while the ideality factor (n) decreased with the increase in temperature. Such a temperature dependent behavior of $${\phi _{ap}}$$ and n was explained by the inhomogeneity of $${\phi _{ap}}$$ , which obeyed Gaussian distribution with zero-bias mean barrier height ( $${\bar {\phi }_{B0}}$$ ) of 1.02 ± 0.02 eV and standard deviation ( $${\sigma _{s0}}$$ ) of 153 ± 0.04 mV. Subsequently, $${\bar {\phi }_{B0}}$$ and Richardson constant A* were obtained from the slope and intercept of the modified Richardson plot as 0.99 ± 0.01 e V and 67.2 A cm−2 K−2, respectively. The $${\bar {\phi }_{B0}}$$ obtained from the modified Richardson plot was in good agreement with the theoretical value calculated from the work function of Ni and electron affinity of β-Ga2O3. The I–V–T characteristics of Ni/β-Ga2O3/GaN MOS structures can be successfully explained by the thermionic emission theory with a single Gaussian distribution of the barrier height.

Junction properties analysis of silicon back-to-back Schottky diode with reduced graphene oxide Schottky electrodes

Reduced graphene oxide (rGO)/silicon (Si) Schottky junction possesses promising attributes for various applications such as chemical sensor and photodetector. In this paper, a fabrication of simple back-to-back rGO/Si Schottky junction structure is presented. The device was fabricated via wet processes such as vacuum filtration, patterning by delamination, wet transfer and chemical reduction by ascorbic acid. From the current-voltage measurement, series resistance, barrier height and ideality factor were investigated at different temperature. Barrier height increases and ideality factor decreases with the increase of temperature indicating the inhomogeneity of the junction interface. By considering the Gaussian distribution of barrier height, the fabricated Schottky junction was shown to possess the mean barrier height of 1.24 eV with standard deviation value of 0.16 eV. The obtained mean barrier height was larger than the bandgap of Si, indicating the presence of thin insulation layer at the interface.

Effect of inhomogeneous Schottky barrier height of SnO2 nanowires device

The current–voltage (I–V) characteristics of metal–semiconductor junction (Au–Ni/SnO2/Au–Ni) Schottky barrier in SnO2 nanowires were investigated over a wide temperature range. By using the Schottky–Mott model, the zero bias barrier height ΦB was estimated from I–V characteristics, and it was found to increase with increasing temperature; on the other hand the ideality factor (n) was found to decrease with increasing temperature. The variation in the Schottky barrier and n was attributed to the spatial inhomogeneity of the Schottky barrier height. The experimental I–V characteristics exhibited a Gaussian distribution having mean barrier heights of 0.30 eV and standard deviation σs of 60 meV. Additionally, the Richardson modified constant was obtained to be 70 A cm−2 K−2, leading to an effective mass of 0.58m0. Consequently, the temperature dependence of I–V characteristics of the SnO2 nanowire devices can be successfully explained on the Schottky–Mott theory framework taking into account a Gaussian distribution of barrier heights.