The electron transport within bulk wurtzite zinc oxide in response to strong applied electric field pulses

2013 ◽  
Vol 1577 ◽  
Author(s):  
Walid A. Hadi ◽  
Michael S. Shur ◽  
Stephen K. O’Leary
Keyword(s):  
Zinc Oxide ◽  
Electron Transport ◽  
Electric Field ◽  
Electric Fields ◽  
Drift Velocity ◽  
High Field ◽  
Electronic Devices ◽  
Average Energy ◽  
High Field Strength ◽  
High Electric Fields

ABSTRACTStrong short electric field pulses are used to generate broadband terahertz radiation. Understanding the transport properties under such conditions is very important for the understanding of numerous terahertz photonic and electronic devices. In this paper, we report on transport simulations of the electrons within bulk wurtzite zinc oxide for pulsed high electric fields, with pulse durations of up to 400 fs. We focus on how key electron transport characteristics, namely the drift velocity and the corresponding average energy, vary with time since the onset of the pulse. For sufficiently high-field strength selections, we find that both of these parameters exhibit peaks. In addition, an electron drift velocity undershoot is observed following this peak. A contrast with the case of gallium nitride is considered; undershoot is not observed for the case of this material. Reasons for these differences in behavior are suggested.

scholarly journals Electron Transport Characteristics of Wurtzite GaN

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
F. M. Abou El-Ela ◽  
A. Z. Mohamed
Keyword(s):  
Relaxation Time ◽  
Electron Transport ◽  
Electric Field ◽  
Electric Fields ◽  
Drift Velocity ◽  
Differential Resistance ◽  
Polar Optical Phonon ◽  
Average Electron Energy ◽  
Wide Range ◽  
High Electric Fields

A three-valley Monte Carlo simulation approach was used to investigate electron transport in wurtzite GaN such as the drift velocity, the drift mobility, the average electron energy, energy relaxation time, and momentum relaxation time at high electric fields. The simulation accounted for polar optical phonon, acoustic phonon, piezoelectric, intervalley scattering, and Ridley charged impurity scattering model. For the steady-state transport, the drift velocity against electric field showed a negative differential resistance of a peak value of 2.9×105 m/s at a critical electric field strength 180×105 V/m. The electron drift velocity relaxes to the saturation value of 1.5×105 m/s at very high electric fields. The electron velocities against time over wide range of electric fields are reported.

HIGH-FIELD ELECTRON TRANSPORT CONTROLLED BY OPTICAL PHONON EMISSION IN NITRIDES

2002 ◽  
Vol 12 (04) ◽  
pp. 1057-1081 ◽  
Author(s):  
S. M. KOMIRENKO ◽  
K. W. KIM ◽  
V. A. KOCHELAP ◽  
M. A. STROSCIO
Keyword(s):  
Electron Transport ◽  
Electric Fields ◽  
High Field ◽  
Transport Model ◽  
Group Iii Nitrides ◽  
Electron Velocity ◽  
Electron Velocity Distribution ◽  
Group Iii ◽  
Field Electron ◽  
High Electric Fields

We have investigated the problem of electron runaway at strong electric fields in polar semiconductors focusing on the nanoscale nitride-based heterostructures. A transport model which takes into account the main features of electrons injected in short devices under high electric fields is developed. The electron distribution as a function of the electron momenta and coordinate is analyzed. We have determined the critical field for the runaway regime and investigated this regime in detail. The electron velocity distribution over the device is studied at different fields. We have applied the model to the group-III nitrides: InN, GaN and AlN. For these materials, the basic parameters and characteristics of the high-field electron transport are obtained. We have found that the transport in the nitrides is always dissipative. However, in the runaway regime, energies and velocities of electrons increase with distance which results in average velocities higher than the peak velocity in bulk-like samples. We demonstrated that the runaway electrons are characterized by the extreme distribution function with the population inversion. A three-terminal heterostructure where the runaway effect can be detected and measured is proposed. We also have considered briefly different nitride-based small-feature-size devices where this effect can have an impact on the device performance.

scholarly journals Low- and high-field electromechanical responses of relaxor-based multicomponent ceramics for application in multiregime actuators

2020 ◽  
Vol 10 (01n02) ◽  
pp. 2060004
Author(s):  
M. V. Talanov ◽  
A. A. Pavelko ◽  
L. A. Reznichenko
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Solid Solutions ◽  
High Field ◽  
Piezoelectric Coefficient ◽  
Large Signal ◽  
Electromechanical Responses ◽  
High Electric Fields

The electromechanical responses of multicomponent solid solutions [Formula: see text][Formula: see text]([Formula: see text][Formula: see text])[Formula: see text]([Formula: see text][Formula: see text])[Formula: see text]([Formula: see text][Formula: see text])[Formula: see text][Formula: see text]O3 in low and high electric fields were studied. In both cases, significant electromechanical responses are observed. In particular, the maximum values of the large-signal piezoelectric coefficient [Formula: see text] reach 1600[Formula: see text]m/V at very low values of the electric field ([Formula: see text]5[Formula: see text]kV/cm). The observed features of the electromechanical responses of the studied ceramics are advantages in terms of their possible application in actuators.

High field properties of electron transport in bulk zincblende In0.53Ga0.47As and In0.53Ga0.47Sb

2015 ◽  
Vol 29 (10) ◽  
pp. 1550038
Author(s):  
Amir Akbari Tochaei
Keyword(s):  
Electron Transport ◽  
Electric Field ◽  
Electric Fields ◽  
High Field ◽  
High Electric Field ◽  
Threshold Field ◽  
Ensemble Monte Carlo ◽  
Velocity Peak ◽  
Electron Transport Properties ◽  
Ternary Semiconductors

In this paper, electron transport properties in bulk zincblende In 0.53 Ga 0.47 As and In 0.53 Ga 0.47 Sb in high electric field are presented by using an ensemble Monte Carlo method. The steady state electron transport and transient situation in these two ternary semiconductors are reviewed and compared together by the three-valley model of conduction band. The results show that In 0.53 Ga 0.47 Sb has lower threshold field and higher drift velocity peak in comparison with In 0.53 Ga 0.47 As . Moreover, In 0.53 Ga 0.47 Sb has higher overshoot velocity and shorter time response in high electric field in comparison with In 0.53 Ga 0.47 As . However, overshoot relaxation time is equal for them in two applied electric fields.

High Field Electron Drift in a-Si:H

1993 ◽  
Vol 297 ◽  
Author(s):  
Qing Gu ◽  
Eric A. Schiff ◽  
Jean Baptiste Chevrier ◽  
Bernard Equer
Keyword(s):  
Electric Fields ◽  
High Field ◽  
Drift Mobility ◽  
Time Range ◽  
Electron Drift ◽  
Parameter Change ◽  
Transient Photocurrent ◽  
Field Mobility ◽  
High Electric Fields ◽  
Electron Drift Mobility

We have measured the electron drift mobility in a-Si:H at high electric fields (E ≤ 3.6 x 105 V%cm). The a-Si:Hpin structure was prepared at Palaiseau, and incorporated a thickp+ layer to retard high field breakdown. The drift mobility was obtained from transient photocurrent measurements from 1 ns - 1 ms following a laser pulse. Mobility increases as large as a factor of 30 were observed; at 77 K the high field mobility de¬pended exponentially upon field (exp(E/Eu), where E u= 1.1 x 105 V%cm). The same field dependence was observed in the time range 10 ns – 1 μs, indicating that the dispersion parameter change with field was negligible. This latter result appears to exclude hopping in the exponential conduction bandtail as the fundamental transport mechanism in a-Si:H above 77 K; alternate models are briefly discussed.

TEMPERATURE DEPENDENCE OF HIGH FIELD ELECTRON TRANSPORT PROPERTIES IN WURTZITE PHASE GaN FOR DEVICE MODELING

2008 ◽  
Vol 22 (22) ◽  
pp. 3915-3922 ◽  
Author(s):  
A. R. BINESH ◽  
H. ARABSHAHI ◽  
G. R. EBRAHIMI ◽  
M. REZAEE ROKN-ABADI
Keyword(s):  
Electron Transport ◽  
Electric Fields ◽  
Dominant Role ◽  
Electron Velocity ◽  
Differential Conductance ◽  
Device Modeling ◽  
Wurtzite Phase ◽  
Ensemble Monte Carlo ◽  
Electron Transport Properties ◽  
High Electric Fields

An ensemble Monte Carlo simulation has been used to model bulk electron transport at room and higher temperatures as a function of high electric fields. Electronic states within the conduction band valleys at the Γ1, U, M, Γ3 and K are represented by non-parabolic ellipsoidal valleys centred on important symmetry points of the Brillouin zone. The simulation shows that intervalley electron transfer plays a dominant role in GaN in high electric fields leading to a strongly inverted electron distribution and to a large negative differential conductance. Our simulation results have also shown that the electron velocity in GaN is less sensitive to temperature than in other III-V semiconductors like GaAs . So GaN devices are expected to be more tolerant to self-heating and high ambient temperature device modeling. Our steady state velocity-field characteristics are in fair agreement with other recent calculations.

Effect of a High Electric Field on the Thermal and Phase Change Characteristics of an Impacting Drop

2019 ◽  
Author(s):  
Abhishek Basavanna ◽  
Prajakta Khapekar ◽  
Navdeep Singh Dhillon
Keyword(s):  
Heat Transfer ◽  
Electric Field ◽  
Phase Change ◽  
Electric Fields ◽  
High Speed ◽  
Impact Behavior ◽  
Liquid Drops ◽  
Active Interest ◽  
Post Impact ◽  
High Electric Fields

Abstract The effect of applied electric fields on the behavior of liquids and their interaction with solid surfaces has been a topic of active interest for many decades. This has important implications in phase change heat transfer processes such as evaporation, boiling, and condensation. Although the effect of low to moderate voltages has been studied, there is a need to explore the interaction of high electric fields with liquid drops and bubbles, and their effect on heat transfer and phase change. In this study, we employ a high speed optical camera to study the dynamics of a liquid drop impacting a hot substrate under the application of high electric fields. Experimental results indicate a significant change in the pre- and post-impact behavior of the drop. Prior to impact, the applied electric field elongates the drop in the direction of the electric field. Post-impact, the recoil phase of the drop is significantly affected by charging effects. Further, a significant amount of micro-droplet ejection is observed with an increase in the applied voltage.

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