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Unable to Resist
Published in Sharon Ann Holgate, Understanding Solid State Physics, 2021
As we have just learned, unlike metals in which only electrons carry charge, both electrons and holes carry charge in semiconductors. The movement of charge carriers under the influence of an electric field is known as the drift current, and the average velocity of these carriers is called the drift velocity. The drift velocity, vdr, is related to the strength of the electric field, ε, in the following way: vdr=με
Electronic Transport Properties of Skutterudites
Published in Ctirad Uher, Thermoelectric Skutterudites, 2021
As the temperature increases, the lattice atoms oscillate with the increasing amplitude about their equilibrium positions, periodically expanding and compressing the lattice. This gives rise to local density fluctuations that alter the periodic potential and cause small shifts in the energy of the conduction and/or valence band edges, δEc and δEv, respectively. Charge carriers are sensitive to such changes, as they impede their drift velocity acquired by the influence of the electric field or temperature gradient. While in a monoatomic solid the vibrations are strictly of acoustic nature, optical vibrations are usually also important, if not the dominant, scattering mechanism in systems with more than a single atom in a unit cell. The formalism describing the scattering of charge carriers by acoustic vibrations was developed by Bardeen and Shockley (1950) by invoking the concept of the deformation potential scattering.
Transport Properties of Materials
Published in Joel L. Plawsky, Transport Phenomena Fundamentals, 2020
When we apply an electric field to the metal, the electrons alter their random motion and begin to drift along the potential gradient with a drift velocity, vd, that is much less than the mean velocity, v¯. The drift velocity can be determined by the magnitude of the applied electric field, the mean velocity, and the mean free path between collisions. The applied electric field exerts a force on each electron and gives the electron an acceleration, a. Using Newton's second law, that acceleration can be written as: a=eEme
Asymmetry Switching Behavior of the Binary Memristor
Published in IETE Journal of Research, 2022
Mohammad Saeed Feali, Arash Ahmadi, Mohsen Hayati
One way of minimizing is to increase the temperature. According to Equation (9), increasing temperature has two opposite effects on the drift velocity, increasing the and decreasing the . Table 4 shows the effect of various temperatures on the switching behavior of the memristor. As shown in this figure, increasing temperature leads to increasing of the drift velocity. Because the value of is higher than that of , so the exponential function compared to the hyperbolic function has a greater impact on the drift velocity when the temperature changes. As expected, the asymmetry between set and reset times is reduced by the increasing temperature.
Design of 30 nm multi-finger gate GaN HEMT for high frequency device
Published in International Journal of Electronics, 2023
Lijun He, Boyang Zhao, Kang Ma, Chengyun He, Zhiyang Xie, Xing Long, Chaopeng Zhang, Liang She, Fei Qi, Nan Zhang
When the carrier accelerates in the electric field, the electric field becomes large, the speed of the carrier does not increase all the time, but slowly tends to a stable speed and reaches saturation. This is because the drift velocity is not only related to the electric field, but also to the mobility of the carriers, and the reason why the carrier velocity does not increase all the time is the decrease in its mobility. The following expression is a Fldmob model for electric field-related mobility. This provides a smooth transition between low and high electric field behaviour as follows:
Demonstration of Temperature-Dependent Analysis of GAA – β-(AlGa)2O3/Ga2O3 High Electron Mobility Transistor
Published in IETE Journal of Research, 2022
Ravi Ranjan, Nitesh Kashyap, Ashish Raman
The electron velocity of the proposed device across the channel is given in Figure 3(c). The drift velocity of the device is directly proportional to electron mobility, and it reduces with an increase in temperature. Figure 3(d) and 3(e) are the plots of drain current in linear and log scale, respectively, with an increase in temperature. Due to larger electron mobility at a lower temperature, the drain current is larger. ION is 750 mA/mm and 150 mA/mm at 50 and 300 K, respectively. The OFF-state current is too low, and it is in the order of 10−11 (A/µm). The GAA structure is used to increase the ION/IOFF ratio.