High-temperature sensitivity complex dielectric/electric modulus, loss tangent, and AC conductivity in Au/(S -DLC)/p-Si (MIS) structures
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2024-01-01 |
| Journal | Journal of Materials Science Materials in Electronics |
| Authors | A. Tataroğlu, Hülya Durmuş, A. Feizollahi Vahid, Barış Avar, Ş. Altındal |
| Institutions | Selçuk University, Gazi University |
| Citations | 16 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled “Executive Summary”- Device Architecture: A Metal-Interlayer-Semiconductor (MIS) structure, Au/(S:DLC)/p-Si, was fabricated using Sulfur-doped Diamond-Like Carbon (S:DLC) as the interlayer via an electrodeposition method.
- High Dielectric Performance: The structure exhibits a high real dielectric constant (ε’) value, reaching approximately 14 (even at 100 kHz), indicating significant charge storage capability suitable for high-density capacitors.
- Temperature Sensitivity: The device demonstrates extremely high temperature sensitivity (S = dV/dT), measured up to -28 mV/K, confirming its potential application as a highly sensitive temperature sensor.
- Thermal Activation: Electrical parameters (capacitance, conductance, and AC conductivity) show strong thermal activation, increasing rapidly above room temperature (260 K) due to thermally generated electronic charges.
- Conduction Mechanism: Analysis via the Arrhenius plot reveals two distinct conduction regions. At high temperatures (260-440 K), the dominant mechanism is the hopping of electronic charges between interface traps, characterized by a high activation energy (Ea ≈ 189 meV).
- Frequency Dependence: Dielectric parameters decrease with increasing frequency, attributed to the inability of interface states (Nss) and dipoles to follow the AC signal at shorter time periods.
Technical Specifications
Section titled “Technical Specifications”| Parameter | Value | Unit | Context |
|---|---|---|---|
| Device Structure | Au/(S:DLC)/p-Si | MIS | Metal-Interlayer-Semiconductor |
| Interlayer Material | Sulfur-doped Diamond-Like Carbon (S:DLC) | N/A | Electrodeposited |
| Measurement Temperature Range | 80 to 440 | K | Electrical characterization range |
| Measurement Frequencies | 0.1 and 0.5 | MHz | Admittance/Impedance testing |
| High-T Activation Energy (Ea) | 189.41 | meV | Region 2 (260-440 K) at 500 kHz |
| Low-T Activation Energy (Ea) | 5.78 | meV | Region 1 (80-230 K) at 500 kHz |
| Maximum Dielectric Constant (ε’) | ~14 | N/A | Observed at 100 kHz (high T) |
| High Temperature Sensitivity (S = dV/dT) | -28 | mV/K | At 100 kHz, C = 0.7 nF |
| High Temperature Sensitivity (S = dV/dT) | -24 | mV/K | At 500 kHz, C = 0.4 nF |
| S:DLC Film Morphology | Continuous, crack-free, lumpy | N/A | Confirmed by SEM analysis |
| XPS S 2p Binding Energy | 167.8 | eV | Assigned to sulfide compounds (C-S-C, H2S) |
Key Methodologies
Section titled “Key Methodologies”- Electrolyte Preparation: The electrolyte solution was prepared by mixing 100 ml methanol (carbon source) and 100 µl thiophene (sulfur source).
- Electrodeposition Setup: A two-electrode setup was utilized, using a graphite plate as the anode and the p-Si substrate as the cathode.
- Deposition Parameters:
- Distance between electrodes: 4 mm.
- Applied potential: 500 V.
- Duration time: 2 hours.
- Morphological and Chemical Characterization:
- Scanning Electron Microscopy (SEM) was used to confirm the continuous, crack-free nature of the S:DLC film.
- X-Ray Photoelectron Spectroscopy (XPS) was used to confirm the successful doping of sulfur into the DLC film (C 1s and S 2p spectra analysis).
- Electrical Measurement Setup: The Au/(S:DLC)/p-Si device was placed into a VPF-475 cryostat for temperature control (80 K to 440 K).
- Admittance/Impedance Testing: An HP-4192A LF impedance analyzer was used to perform C-V-T and G/ω-V-T measurements across the voltage range of -4 V to +8 V at 0.1 MHz and 0.5 MHz.
- Conduction Analysis: Activation energy (Ea) was determined by plotting the AC conductivity (ln(σac)) versus inverse temperature (1/T) using the Arrhenius equation.
Commercial Applications
Section titled “Commercial Applications”The unique high-temperature sensitivity and high dielectric constant of the Au/(S:DLC)/p-Si structure make it valuable for several advanced electronic applications:
- High-Density Energy Storage: The high dielectric constant (ε’ ≈ 14) indicates superior charge storage capability, making the material suitable for high-performance capacitors used in power electronics and filtering circuits.
- High-Temperature Sensing: The exceptional temperature sensitivity (up to -28 mV/K) allows the device to function effectively as a highly accurate temperature sensor, particularly in environments operating above room temperature (260-440 K).
- Power Electronics and Switching: As a Metal-Interlayer-Semiconductor (MIS) Schottky contact, the device inherits beneficial properties over standard P/N junctions, including high power capacity and high-speed switching elements.
- Radiation-Hardened Devices: DLC films are known for their robustness. The use of S:DLC could lead to stable electronic components (capacitors, transistors) capable of operating reliably in harsh or high-temperature environments.
- Photovoltaics and Photodiodes: The base MIS structure is widely used in solar cells and photodetectors, where the interlayer properties are critical for controlling barrier height and improving efficiency.
View Original Abstract
Abstract Complex dielectric ( ε * = ε′ − jε″ )/electric modulus ( M * = M′ + jM ″), loss tangent (tan δ ), and ac conductivity ( σ ac ) properties of Au/(S-DLC)/p-Si structures were investigated by utilizing admittance/impedance measurements between 80 and 440 K at 0.1 and 0.5 MHz. Sulfur-doped diamond-like carbon (S:DLC) was used an interlayer at Au/p-Si interface utilizing electrodeposition method. The capacitance/conductance (C/G) or ( ε ’ ~ C) and ( ε ″ ~ G) values found to be highly dependent on both frequency and temperature. The increase of them with temperatures was attributed to the thermal-activated electronic charges localized at interface states ( N ss ) and decrease in bandgap energy of semiconductor. The observed high ε ′ and ε ″ values at 0.1 MHz is the result of the space/dipole polarization and N ss . Because the charges are at low frequencies, dipoles have sufficient time to rotation yourself in the direction of electric field and N ss can easily follow the ac signal. Arrhenius plot (ln( σ ac ) vs 1/ T ) shows two distinctive linear parts and activation energy ( E a ) value was found as 5.78 and 189.41 from the slope; this plot at 0.5 MHz is corresponding to low temperature (80-230 K) and high temperature (260-440 K), respectively. The observed higher E a and ε ′ (~ 14 even at 100 kHz) show that hopping of electronic charges from traps to others is predominant charge transport mechanism and the prepared Au/(S:DLC)/p-Si structure can be used to store more energy.