Frequency and voltage dependence of negative capacitance in Au/SiO2/n-GaAs structures

The frequency (f) and bias voltage (V) dependence of electrical and dielectric properties of Au/SiO₂/n-GaAs structures have been investigated in the frequency range of 10 kHz–3 MHz at room temperature by considering the presence of series resistance (R_s). The values of R_s, dielectric constant (ε′), dielectric loss (ε″) and dielectric loss tangent (tan δ) of these structures were obtained from capacitance–voltage (C–V) and conductance–voltage (G/ω–V) measurements and these parameters were found to be strong functions of frequency and bias voltage. In the forward bias region, C–V plots show a negative capacitance (NC) behavior, hence ε′–V plots for each frequency value take negative values as well. Such negative values of C correspond to the maximum of the conductance (G/ω). The crosssection of the C–V plots appears as an abnormality when compared to the conventional behavior of ideal Schottky barrier diode (SBD), metal–insulator–semiconductor (MIS) and metal–oxide–semiconductor (MOS) structures. Such behavior of C and ε′ has been explained with the minority-carrier injection and relaxation theory. Experimental results show that the dielectric properties of these structures are quite sensitive to frequency and applied bias voltage especially at low frequencies because of continuous density distribution of interface states and their relaxation time.     

The roles of dendritic spacings and Ag3Sn intermetallics on hardness of the SAC307 solder alloy

Sn–Ag–Cu alloys have emerged as the most promising lead-free solder series among a number of alternatives. These alloys generally present a dendritic Sn-rich matrix surrounded by a eutectic mixture (β + α), where β is the Sn-rich phase and α is the Ag₃Sn intermetallic compound. The present study aims to investigate the effects of dendritic (λ₂, λ₃) and eutectic (λ) spacings and the morphology of Ag₃Sn particles on hardness of the Sn–3.0 wt%Ag–0.7 wt%Cu alloy (SAC307). In order to establish correlations between λ_2,3 and hardness, transient directional solidification (DS) experiments were performed permitting a wide range of different microstructures to be examined. The techniques used for microstructure characterization included dissolution of the Sn-rich matrix, optical/scanning electron microscopy. A dendritic microstructure prevailed in the entire DS casting. It is shown that the hardness tends to decrease with the increase in λ₂, λ₃ and λ_F (eutectic spacing for Ag₃Sn having a fiber morphology). Experimental equations relating microstructural spacings to hardness are proposed.     

Evaluation of lateral barrier height of inhomogeneous photolithography-fabricated Au/n-GaAs Schottky barrier diodes from 80 K to 320 K

In order to evaluate current conduction mechanism in the Au/n-GaAs Schottky barrier diode (SBD) some electrical parameters such as the zero-bias barrier height (BH) Φ_bo(I–V) and ideality factor (n) were obtained from the forward bias current–voltage (I–V) characteristics in wide temperature range of 80–320 K by steps of 10 K. By using the thermionic emission (TE) theory, the Φ_bo(I–V) and n were found to depend strongly on temperature, and the n decreases with increasing temperature while the Φ_bo(I–V) increases. The values of Φ_bo and n ranged from 0.600 eV and 1.51(80 K) to 0.816 eV and 1.087 (320 K), respectively. Such behavior of Φ_bo and n is attributed to Schottky barrier inhomogeneities by assuming a Gaussian distribution (GD) of BHs at Au/n-GaAs interface. In the calculations, the electrical parameters of the experimental forward bias I–V characteristics of the Au/n-GaAs SBD with the homogeneity in the 80–320 K range have been explained by means of the TE, considering GD of BH with linear bias dependence.     

Theoretical analysis of characteristics for 2 μm Tm3+:Ho3+ co-doped silica fiber laser pumped by a 1550 nm fiber laser

We established a theoretical model of 2 μm Tm³⁺:Ho³⁺ co-doped silica fiber laser pumped by a 1550 nm fiber laser based on the rate-equation theory and performed the numerical simulation using Runge–Kutta algorithm and Newton–Raphson algorithm. The intracavity power distributions of both pump and laser of the Tm³⁺:Ho³⁺ co-doped silica fiber laser based on the Tm³⁺:Ho³⁺ co-doped silica fiber supplied by the National Optics Institute in Canada (NOIC) were obtained. The effects of the output reflectivity R₄(λ_s) at the output laser wavelength λ_s and the concentrations of Tm³⁺ and Ho³⁺ in the fiber on laser output performance were analyzed. In order to achieve a high laser output power, the optimal R₄(λ_s) of 0.13 was verified and the optimal Tm:Ho ratio of 1:2.4 was proposed. Finally, better output performance for the fiber laser based on the optimized Tm³⁺:Ho³⁺ co-doped silica fiber was obtained than the laser using the fiber supplied by the NOIC. This theoretical model and numerical simulation results will guide the fabrication of 2 μm Tm³⁺:Ho³⁺ co-doped all-fiber lasers pumped by 1600-nm-band (1500–1750 nm) Er³⁺:Yb³⁺ co-doped silica fiber lasers.     

Tin naphthalocyanine complexes for infrared absorption in organic photovoltaic cells

In this work, we examine the optical properties of tin naphthalocyanine dichloride (SnNcCl₂), and its performance as an electron donor material in organic photovoltaic cells (OPVs). As an active material, SnNcCl₂ is attractive for its narrow energy gap which facilitates optical absorption past a wavelength of λ = 1100 nm. We demonstrate a power conversion efficiency of η_P = (1.2 ± 0.1)% under simulated AM1.5G solar illumination at 100 mW/cm² using the electron donor–acceptor pairing of SnNcCl₂ and C₆₀ in a bilayer device architecture. While some phthalocyanines have been previously used to improve infrared absorption, this is often realized through the formation of molecular dimers. In SnNcCl₂, the infrared absorption is intrinsic to the molecule, arising as a result of the extended conjugation. Consequently, it is expected that SnNcCl₂ could be utilized in bulk heterojunction OPVs without sacrificing infrared absorption.     

Temperature dependent dielectric studies of Ni/n-GaP Schottky diodes by capacitance and conductance measurements

The dielectric properties of Ni/n-GaP Schottky diode were investigated in the temperature range 140–300 K by capacitance–voltage (C–V) and conductance–voltage (G/ω–V) measurements. The effect of temperature on series resistance (R_s) and interface state density (N_ss) were investigated. The dependency of dielectric constant (ε′), dielectric loss (ε′′), loss tangent (tan δ), ac conductivity (σ_ac), real (M′) and imaginary (M′′) parts of the electric modulus over temperature were evaluated and analyzed at 1 MHz frequency. The temperature dependent characteristics of ε′ and ε′′ reveal the contribution of various polarization effects, which increases with temperature. The Arrhenius plot of σ_ac shows two activation energies revealing the presence of two distinct trap states in the chosen temperature range. Moreover, the capacitance–frequency (C–f) measurement over 1 kHz to 1 MHz was carried out to study the effect of localized interface states.     

Sb2(SxSe1−x)3 sensitized solar cells prepared by solution deposition methods

Solid state semiconductor sensitized solar cells are a very active research subject in emerging photovoltaic technologies. In this work, heterojunctions of antimony sulfide-selenide (Sb₂(S_xSe_1−x)₃) solid solution as the absorbing material and cadmium sulfide coated titanium dioxide (TiO₂/CdS) as the electron conductor have been developed with solution deposition methods such as spin-coating, successive ionic layer adsorption and reaction (SILAR), and chemical bath deposition. In particular, CdS has been deposited on mesoporous TiO₂ layers by SILAR deposition, followed by the chemical deposition of Sb₂(S_xSe_1−x)₃. It was found that by increasing the number of CdS SILAR deposition, both the open circuit voltage V_oc and the short circuit current density J_sc of the Sb₂(S_xSe_1−x)₃ sensitized solar cells had been increased from 153 to 434 mV and 0.77–9.73 mA/cm², respectively. This improvement was attributed to the fact that the presence of the CdS on TiO₂ surface reduces the formation of undesired Sb₂O₃ and promotes a better nucleation of the Sb₂(S_xSe_1−x)₃ during the chemical bath deposition. The best result was obtained for the solar cell with 30 cycles of CdS which produced a V_oc of 434 mV, a J_sc of 9.73 mA/cm², and a power conversion efficiency of 1.69% under AM1.5 G solar radiation.     

Self-aligned inversion n-channel In0.2Ga0.8As/GaAs metal–oxide–semiconductor field-effect-transistors with TiN gate and Ga2O3(Gd2O3) dielectric

A self-aligned process for fabricating inversion n-channel metal–oxide–semiconductor field-effect-transistors (MOSFET’s) of strained In_0.2Ga_0.8As on GaAs using TiN as gate metal and Ga₂O₃(Gd₂O₃) as high κ gate dielectric has been developed. A MOSFET with a 4 μm gate length and a 100 μm gate width exhibits a drain current of 1.5 mA/mm at V_g = 4 V and V_d = 2 V, a low gate leakage of <10^?7 A/cm² at 1 MV/cm, an extrinsic transconductance of 1.7 mS/mm at V_g = 3 V, V_d = 2 V, and an on/off ratio of ～10⁵ in drain current. For comparison, a TiN/Ga₂O₃(Gd₂O₃)/In_0.2Ga_0.8As MOS diode after rapid thermal annealing (RTA) to high temperatures of 750 °C exhibits excellent electrical and structural performances: a low leakage current density of 10^?8–10^?9 A/cm², well-behaved capacitance–voltage (C–V) characteristics giving a high dielectric constant of ～16 and a low interfacial density of state of ～(2～6) × 10¹¹ cm^?2 eV^?1, and an atomically sharp smooth Ga₂O₃(Gd₂O₃)/In_0.2Ga_0.8As interface.     

Microwave dielectric properties of (1 − x)(Mg0.95Co0.05)TiO3– xCa0.6La0.8/3TiO3 ceramics with V2O5 addition

The microstructures and the microwave dielectric properties of the (1 − x)(Mg_0.95Co_0.05)TiO₃–xCa_0.6La_0.8/3TiO₃ ceramic system were investigated. In order to achieve a temperature-stable material, we studied a method of combining a positive temperature coefficient material with a negative one. Ca_0.6La_0.8/3TiO₃ has dielectric properties of dielectric constant ε_r ∼ 109, Q × f value ∼ 17,600 GHz and a large positive τ_f value ∼ 213 ppm/°C. (Mg_0.95Co_0.05)TiO₃ ceramics possesses high dielectric constant (ε_r ∼ 16.8), high quality factor (Q × f value ∼ 230,000 GHz), and negative τ_f value (−54 ppm/°C). As the x value varies from 0.1 to 0.8, (1 − x)(Mg_0.95Co_0.05)TiO₃–xCa_0.6La_0.8/3TiO₃ ceramic system has the dielectric properties as follows: 21.55 < ε_r < 75.44, 21,000 < Q × f < 90,000 and −10 < τ_f < 140. By appropriately adjusting the x value in the (1 − x)(Mg_0.95Co_0.05)TiO₃–xCa_0.6La_0.8/3TiO₃ ceramic system, zero τ_f value can be achieved. With x = 0.15, a dielectric constant ε_r ∼ 25.78, a Q × f value ∼ 84,000 GHz (at 9 GHz), and a τ_f value ∼ 2 ppm/°C were obtained for 0.85(Mg_0.95Co_0.05)TiO₃–0.15Ca_0.6La_0.8/3TiO₃ ceramics sintered at 1400 °C for 4 h. For practical application in communication systems, it is desirable to be able to sinter at lower temperatures. Therefore, V₂O₅ was as a sintering aid for lowering the sintering temperature of0.85(Mg_0.95Co_0.05)TiO₃–0.15Ca_0.6La_0.8/3TiO₃ ceramics. At the same time, the 0.85(Mg_0.95Co_0.05)TiO₃–0.15Ca_0.6La_0.8/3TiO₃ ceramic system with 0.5 wt% V₂O₅ can be obtained good properties at the microwave frequencies for 1200 °C.     

The temperature dependent analysis of Au/TiO2 (rutile)/n-Si (MIS) SBDs using current–voltage–temperature (I–V–T) characteristics

In this study, the main electrical parameters of Au/TiO₂(rutile)/n-Si Schottky barrier diodes (SBDs) were analyzed by using current–voltage–temperature (I–V–T) characteristics in the temperature range 200–380 K. Titanium dioxide (TiO₂) thin film was deposited on a polycrystalline n-type Silicon (Si) substrate using the DC magnetron sputtering system at 200 °C. In order to improve the crystal quality deposited film was annealed at 900 °C in air atmosphere for phase transition from amorphous to rutile phase. The barrier height (Φ_b) and ideality factor (n) were calculated from I–V characteristics. An increase in the value of Φ_b and a decrease in n with increasing temperature were observed. The values of Φ_b and n for Au/TiO₂(rutile)/n-Si SBDs ranged from 0.57 eV and 3.50 (at 200 K) to 0.82 eV and 1.90 (at 380 K), respectively. In addition, series resistance (R_s) and Φ_b values of MIS SBDs were determined by using Cheung's and Norde's functions. Cheung's plots are obtained from the donward concave curvature region in the forward bias semi-logarithmic I–V curves originated from series resistance. Norde's function is easily used to obtain series resistance as a function of temperature due to current counduction mechanism which is dominated by thermionic emission (TE). The obtained results have been compared with each other and experimental results show that R_s values exhibit an unusual behavior that it increases with increasing temperature.     

Green and blue-green phosphorescent heteroleptic iridium complexes containing carbazole-functionalized β-diketonate for non-doped organic light-emitting diodes

Two novel iridium complexes both containing carbazole-functionalized β-diketonate, Ir(ppy)₂(CBDK) [bis(2-phenylpyridinato-N,C²)iridium(1-(carbazol-9-yl)-5,5-dimethylhexane-2,4-diketonate)], Ir(dfppy)₂(CBDK) [bis(2-(2,4-difluorophenyl)pyridinato-N,C²)iridium(1-(carbazol-9-yl)-5,5-dimethylhexane-2,4-diketonate)] and two reported complexes, Ir(ppy)₂(acac) (acac = acetylacetonate), Ir(dfppy)₂(acac) were synthesized and characterized. The electrophosphorescent properties of non-doped device using the four complexes as emitter, respectively, with a configuration of ITO/N,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′-diphenyl-4,4′-diamine (NPB) (20 nm)/iridium complex (20 nm)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) (5 nm)/tris(8-hydroxyquinoline)aluminum (AlQ) (45 nm)/Mg_0.9Ag_0.1 (200 nm)/Ag (80 nm) were examined. In addition, a most simplest device, ITO/Ir(ppy)₂(CBDK) (80 nm)/Mg_0.9Ag_0.1 (200 nm)/Ag (80 nm), and two double-layer devices with configurations of ITO/NPB (30 nm)/Ir(ppy)₂(CBDK) (30 nm)/Mg_0.9Ag_0.1 (200 nm)/Ag (80 nm) and ITO/Ir(ppy)₂(CBDK) (30 nm)/AlQ (30 nm)/Mg_0.9Ag_0.1 (200 nm)/Ag (80 nm) were also fabricated and examined. The results show that the non-doped four-layer device for Ir(ppy)₂(CBDK) achieves maximum lumen efficiency of 4.54 lm/W and which is far higher than that of Ir(ppy)₂(acac), 0.53 lm/W, the device for Ir(dfppy)₂(CBDK) achieves maximum lumen efficiency of 0.51 lm/W and which is also far higher than that of Ir(dfppy)₂(acac), 0.06 lm/W. The results of simple devices involved Ir(ppy)₂(CBDK) show that the designed complex not only has a good hole transporting ability, but also has a good electron transporting ability. The improved performance of Ir(ppy)₂(CBDK) and Ir(dfppy)₂(CBDK) can be attributed to that the bulky carbazole-functionalized β-diketonate was introduced, therefore the carrier transporting property was improved and the triplet–triplet annihilation was reduced.     

Computational studies on the radiative and nonradiative processes of luminescent N-heteroleptic platinum(II) complexes

Three N-heteroleptic Pt(II) complexes, [Pt(C^C)(O^O)] [O^O = acetylacetonate, C^C = 1-phenyl-1,2,4-triazol-5-ylidene (1), C^C = 4-phenyl-1,2,4-triazol-5-ylidene (2), C^C = 2-phenylpyrazine (3)] have been investigated with density functional theory (DFT) and time-dependent density functional theory (TDDFT). The radiative decay rate constants of complexes 1–3 have been discussed with the oscillator strength (f_n), the strength of spin–orbit coupling (SOC) interaction between the lowest energy triplet excited state (T₁) and singlet excited states (S_n), and the energy gaps between E(T₁) and E(S_n). To illustrate the nonradiative decay processes, the transition states between triplet metal-centered (³MC) and T₁ states have been optimized and were verified with the calculations of vibrational frequencies and intrinsic reaction coordinate (IRC). In addition, the minimum energy crossing points (MECPs) between ³MC and ground states (S₀) were optimized. At last, the potential energy curves relevant to the nonradiative decay pathways are simulated. The results show that complex 3 has the biggest photoluminescence quantum yield because the complex 3 has the biggest radiative decay rate constant and the smallest nonradiative decay rate constant in complexes 1–3.     

Characteristics of RF reactive sputter-deposited Pt/SiO2/n-InGaN MOS Schottky diodes

All RF sputtering-deposited Pt/SiO₂/n-type indium gallium nitride (n-InGaN) metal–oxide–semiconductor (MOS) diodes were investigated before and after annealing at 400 °C. By scanning electron microscopy (SEM), the thickness of Pt, SiO_2, n-InGaN layer was measured to be ~250, 70, and 800 nm, respectively. AFM results also show that the grains become a little bigger after annealing, the surface topography of the as-deposited film was smoother with the rms roughness of 1.67 nm and had the slight increase of 1.92 nm for annealed sample. Electrical properties of MOS diodes have been determined by using the current–voltage (I–V) and capacitance–voltage (C–V) measurements. The results showed that Schottky barrier height (SBH) increased slightly to 0.69 eV (I–V) and 0.82 eV (C–V) after annealing at 400 °C for 15 min in N₂ ambient, compared to that of 0.67 eV (I–V) and 0.79 eV (C–V) for the as-deposited sample. There was the considerable improvement in the leakage current, dropped from 6.5×10⁻⁷ A for the as-deposited to 1.4×10⁻⁷ A for the 400 °C-annealed one. The annealed MOS Schottky diode had shown the higher SBH, lower leakage current, smaller ideality factor (n), and denser microstructure. In addition to the SBH, n, and series resistance (R_s) determined by Cheungs׳ and Norde methods, other parameters for MOS diodes tested at room temperature were also calculated by C–V measurement.     

Laser-induced forward transfer of polythiophene-based derivatives for fully polymeric thin film transistors

Polymeric thin-film transistors (pTFTs) have been fabricated by pulsed-laser printing of semiconductor and conductor polythiophene-based derivatives. Thin solid layers of semiconducting poly(3,3′″ didodecylquaterthiophene) (PQT-12) have been transferred by a laser-induced forward transfer (LIFT) technique on Si/SiO₂ receiver substrates. Optimization of the transfer conditions and of the pixels morphologies has been realized. A marked improvement in the quality of the pixels has been observed, in terms of morphology and structure, by reducing the environmental pressure to 90 mbar during LIFT. Subsequently, poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) has also been laser-printed and used as source/drain electrodes in the transistor configuration. Functional polymeric transistors have been obtained with high field-effect mobility up to 2 × 10⁻² cm² V⁻¹ s⁻¹ together with current modulation of 10⁴.     

p-type LiCr0.33V0.33Mn0.33O2 semiconductor as a cathode electrode for high rate Li-ion batteries

Layered LiCr_0.33V_0.33Mn_0.33O₂ oxides have attracted attention as cathode materials for lithium ion batteries. These materials are good candidates to replace LiCoO₂ used in the commercially available lithium ion batteries. In this study, a systematic work has been performed to investigate the structural and electrochemical behaviors of LiCr_0.33V_0.33Mn_0.33O₂ oxide structures via sol–gel method. In order to increase the conductivity, the surfaces of the as-synthesized LiCr_0.33V_0.33Mn_0.33O₂ oxide structures were coated with Cu via electroless deposition techniques. Powder X-ray diffraction (XRD) was performed on a Rigaku DMAX 2200 diffractometer (Cu Kα radiation, λ=1.5418 Å) between 10° and 90° (2θ) by steps of 0.02° (2θ) with a constant counting time of 10 s/step. Scanning electron microscopy (SEM) was carried out with a Jeol 6060 LV microscope. The electrochemical performances of the LiCr_0.33V_0.33Mn_0.33O₂ samples were measured in the 3.0–4.3 V potential range. Their discharge capacity reached 174 and 181 mA h g⁻¹ at 1 C. This structural stability during the cycling combined with the obtained electrochemical features make these materials convenient for the lithium ion batteries applications.     

105 nm Gate length pMOSFETs with high-K and metal gate fabricated in a Si process line on 200 mm GeOI wafers

We report on the fabrication and electrical characterization of deep sub-micron (gate length down to 105 nm) GeOI pMOSFETs. The Ge layer obtained by hetero-epitaxy on Si wafers has been transferred using the Smart Cut^TM process to fabricate 200 mm GeOI wafers with Ge thickness down to 60–80 nm. A full Si MOS compatible pMOSFET process was implemented with HfO₂/TiN gate stack. The electrical characterization of the fabricated devices and the systematic analysis of the measured performances (I_ON, I_OFF, transconductance, low field mobility, S, DIBL) demonstrate the potential of pMOSFET on GeOI for advanced technological nodes. The dependence of these parameters have been analyzed with respect to the gate length, showing very good transport properties (μ_h ～ 250 cm²/V/s, I_ON = 436 μA/μm for L_G = 105 nm), and OFF current densities comparable or better than those reported in the literature.     

Analysis of recursive convolutional codes and turbo codes as sources with memory

The paper proposes a general method to analyze discrete sources with memory. Besides the classical entropy, we define new information measures for discrete sources with memory, similar to the information quantities specific to discrete channels. On the base of this method, we show for the first time that, as result of convolutional and turbo encoding, sources with memory are obtained. We apply this information analysis method for the general case of a recursive convolutional encoder of rate R_CC = 1/n₀ and memory of order m, and for a turbo encoder of rate R_TC = 1/3, with two systematic recursive convolutional component encoders. Each component encoder has memory of order m, and is built based on the same primitive feedback polynomial. For the convolutional and turbo codes, the information quantities H(Y/S), H(S,Y), H(S/Y), H(Y), H(S) and I(S,Y) have been computed, where S and Y denote the set of states and the set of messages of the encoder, respectively. The analysis considered two cases: n₀ ≤ m + 1 and n₀ > m + 1. When n₀ = m + 1, the mutual information I(S,Y) is maximum and equal to m, as is the entropy of the set of states. For turbo codes, the quantity I(S,Y) also depends on the input bit and on its probability.     

Carrier transport mechanisms and photovoltaic properties of Au/p-ZnPc/Al device

The dark current density–voltage characteristic of Au/ZnPc/Al device at room temperature has been investigated. Results showed a rectification behavior. At low forward bias, the current density was found to be ohmic, while at high voltages, space charge limited the current mechanism dominated by exponential trapping levels. Junction parameters such as rectification ratio (RR), series resistance (R_s), and shunt resistance (R_sh) were found to be 9.42, 9.72 MΩ, and 0.88 × 10³ MΩ, respectively. The current density–voltage characteristics under white light illumination (100 W/m²) gives values of 0.55 V, 3 × 10⁻³ A/m², 0.18 and 5.8 × 10⁻⁴% for the open circuit voltage, V_oc, the short circuit current density (J_sc), the fill factor (FF), and conversion efficiency (η), respectively.     

Photoluminescent and electroluminescent properties and ultra-fast spectrometric studies of dihydroheptacenes

Photophysical and electrochemical properties of 7,16-dihydroheptacenes (1–3) were investigated in detail. Although their HOMO–LUMO gaps are higher than 3 eV, the organic light-emitting diodes containing 1 as the emitting dopant showed green electroluminescence (λ_max ∼ 515 and 550 nm) even at a concentration of the dopant as low as 1%. The green electroluminescence of 1 appears to be originating from an electromeric state (an intermolecular ion pair). The maximum brightness of 190 cd/m² was observed at a current density of 34 mA/cm² at operating voltage of 19 V for the device containing 1% 1, and overall performance of the devices decreased with an increase in the doping concentration of 1.     

Determination of contact parameters of Ni/n-GaP Schottky contacts

The electrical analysis of Ni/n-GaP structure has been investigated by means of current–voltage (I–V), capacitance–voltage (C–V) and capacitance–frequency (C–f) measurements in the temperature range of 120–320 K in dark conditions. The forward bias I–V characteristics have been analyzed on the basis of standard thermionic emission (TE) theory and the characteristic parameters of the Schottky contacts (SCs) such as Schottky barrier height (SBH), ideality factor (n) and series resistance (R_s) have been determined from the I–V measurements. The experimental values of SBH and n for the device ranged from 1.01 eV and 1.27 (at 320 K) to 0.38 eV and 5.93 (at 120 K) for Ni/n-GaP diode, respectively. The interface states in the semiconductor bandgap and their relaxation time have been determined from the C–f characteristics. The interface state density N_ss has ranged from 2.08 × 10¹⁵ (eV^?1 m^?2) at 120 K to 2.7 × 10¹⁵ (eV^?1 m^?2) at 320 K. C_ss has increased with increasing temperature. The relaxation time has ranged from 4.7 × 10^?7 s at 120 K to 5.15 × 10^?7 s at 320 K.