Study of Temperature-dependent Conduction Mechanisms in Au/0.8nm-GaN/n-GaAs Schottky Diode

Passivation of interface states in the Schottky barrier is an approach to enhance the properties of the Schottky devices. In this work, Au/0.8nm-GaN/n-GaAs Schottky structure is studied electrically in a wide temperature range. With increasing temperature, the reverse current Iinv increases from 1×10-7 A to 1×10-5 A, and the saturation current Is increases from 1×10-32 A to 5×10-7A. The series resistance Rs decreases with increasing temperature from 13.44 Ω to 4.25 Ω. The ideality factor n decreases from 10.64 to 1.15. The barrier height increases abnormally with increasing temperature from 0.54 eV at 80 K to 1.03 eV at 180 K, then decreases to 0.82 eV at 420 K. The abnormal behavior of and the high values of n in low temperature are due to the tunnel mechanisms effects, such as FE and TFE currents. FE mechanism is the dominant process at low temperatures (80-300 K) and TFE mechanism is the dominant one at high temperatures (300-420K). Finally, our structure presents an inhomogeneous barrier height, maybe caused by the thin GaN interface layer.

Study on characteristics of schottky temperature detector based on metal/n-ZnO/n-Si structures

Background: At present, the main problems of Micro-Electro-Mechanical Systems (MEMS) temperature detector focus on the narrow range of temperature detection, difficulty of the high temperature measurement. Besides, MEMS devices have different response characteristics for various surrounding temperature in the petrochemical and metallurgy application fields with high-temperature and harsh conditions. To evaluate the performance stability of the hightemperature MEMS devices, the real-time temperature measurement is necessary. Objective: A schottky temperature detector based on the metal/n-ZnO/n-Si structures is designed to measure high temperature (523~873K) for the high-temperature MEMS devices with large temperature range. Method: By using the finite element method (FEM), three different work function metals (Cu, Ni and Pt) contact with the n-ZnO are investigated to realize Schottky. At room temperature (298K) and high temperature (523~873K), the current densities with various bias voltages (J-V) are studied. Results: The simulation results show that the high temperature response power consumption of three schottky detectors of Cu, Ni and Pt decreases successively, which are 1.16 mW, 63.63 μW and 0.14 μW. The response temperature sensitivities of 6.35 μA/K, 0.78 μA/K, and 2.29 nA/K are achieved. Conclusion: The Cu/n-ZnO/n-Si schottky structure could be used as a high temperature detector (523~873K) for the hightemperature MEMS devices. It has a large temperature range (350K) and a high response sensitivity is 6.35 μA/K. Compared with traditional devices, the Cu/n-ZnO/n-Si Schottky structure based temperature detector has a low energy consumption of 1.16 mW, which has potential applications in the high-temperature measurement of the MEMS devices.

Human Respiratory Monitoring Based on Schottky Resistance Humidity Sensors

Two types of Schottky structure sensors (silicon nanowire (SiNW)/ZnO/reduced graphene oxide (rGO) and SiNW/TiO2/rGO) were designed, their humidity resistance characteristics were studied, and the sensors were applied to detect sleep apnea through breath humidity monitoring. The results show that the resistance of the sensors exhibited significant changes with increasing humidity, the response times of the two sensors within the relative humidity range of 23–97% were 49 s and 67 s, and the recovery times were 24 s and 43 s, respectively. Meanwhile, continuous breathing monitoring results indicate that the sensitivity of the sensors remained basically unchanged during 10 min of normal breathing and simulated apnea. The response of the sensor is still good after 30 days of use. We believe that the Schottky structure composite sensor is a very promising technology for human breathing monitoring.

Investigation, analysis and comparison of current-voltage characteristics for Au/Ni/GaN Schottky structure using I-V-T simulation

In this work, we have presented a theoretical study of Au/Ni/GaN Schottky diode based on current-voltage (I-V) measurement for temperature range of 120 K to 400 K. The electrical parameters of Au/Ni/GaN, such as barrier height (Φb), ideality factor and series resistance have been calculated employing the conventional current-voltage (I-V), Cheung and Chattopadhyay method. Also, the variation of Gaussian distribution (P (Φb)) as a function of barrier height (Φb) has been studied. Therefore, the modified ( {( {\ln \left( {{{{\rm{I}}_0 } \over {{\rm{T}}^2 }}} \right) - \left( {{{{\rm{q}}^2 \sigma _{{\rm{s}}0}^2 } \over {2{\rm{kT}}^2 }}} \right) = \ln ( {{\rm{AA}}^*} ) - {{{\rm{q}}\emptyset_{{\rm B}0} } \over {{\rm{kT}}}}} ){\rm{vs}}.( {{1 \over {{\rm{kT}}}}} )} ) relation has been extracted from (I-V) characteristics, where the values of ΦB0 and {\rm{A}}_{{\rm{Simul}}}^* have been found in different temperature ranges. The obtained results have been compared to the existing experimental data and a good agreement was found.