Effect of impact ionization on the saturated drift velocity of charge carriers in semiconductors at high electric field

1975 ◽  
Vol 18 (11) ◽  
pp. 1035-1037 ◽  
Author(s):  
S.K. Roy ◽  
R. Ghosh
Keyword(s):  
Electric Field ◽  
Drift Velocity ◽  
Impact Ionization ◽  
High Electric Field ◽  
Charge Carriers

scholarly journals The Ultimate Ballistic Drift Velocity in Carbon Nanotubes

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
Mohammad Taghi Ahmadi ◽  
Razali Ismail ◽  
Michael L. P. Tan ◽  
Vijay K. Arora
Keyword(s):  
Energy Spectrum ◽  
Electric Field ◽  
Carrier Concentration ◽  
Drift Velocity ◽  
Mean Free Path ◽  
High Electric Field ◽  
Fermi Velocity ◽  
Zero Field ◽  
Saturation Velocity ◽  
The Mean

The carriers in a carbon nanotube (CNT), like in any quasi-1-dimensional (Q1D) nanostructure, have analog energy spectrum only in the quasifree direction; while the other two Cartesian directions are quantum-confined leading to a digital (quantized) energy spectrum. We report the salient features of the mobility and saturation velocity controlling the charge transport in a semiconducting single-walled CNT (SWCNT) channel. The ultimate drift velocity in SWCNT due to the high-electric-field streaming is based on the asymmetrical distribution function that converts randomness in zero-field to a stream-lined one in a very high electric field. Specifically, we show that a higher mobility in an SWCNT does not necessarily lead to a higher saturation velocity that is limited by the mean intrinsic velocity depending upon the band parameters. The intrinsic velocity is found to be appropriate thermal velocity in the nondegenerate regime, increasing with the temperature, but independent of carrier concentration. However, this intrinsic velocity is the Fermi velocity that is independent of temperature, but depends strongly on carrier concentration. The velocity that saturates in a high electric field can be lower than the intrinsic velocity due to onset of a quantum emission. In an SWCNT, the mobility may also become ballistic if the length of the channel is comparable or less than the mean free path.

Drift Velocity of Hot Carriers in a-Se Photoconductive Target

2013 ◽  
Vol 787 ◽  
pp. 337-340 ◽  
Author(s):  
Wug Dong Park ◽  
Kenkichi Tanioka
Keyword(s):  
Relaxation Time ◽  
Electric Field ◽  
Drift Velocity ◽  
Impact Ionization ◽  
Length Ratio ◽  
Multiplication Factor ◽  
Hot Carriers ◽  
Avalanche Multiplication ◽  
Relaxation Length ◽  
The Impact

Avalanche multiplication of the 0.4-μm-thick a-Se HARP (High-gain Avalanche Rushing amorphous Photoconductor) target was obtained at a high electric field. To study the drift velocity of hot carriers in the a-Se layer, the energy-and field-dependent energy relaxation length was considered in the lucky-drift model. The impact ionization energyEIof 2.0 eV and the optical phonon energyћωof 31 meV for a-Se were used to obtain the impact ionization parameters in the a-Se layer. The drift velocity of hot carriers at 1×108V/m in the 0.4-μm-thick a-Se HARP target was obtained as 1.87×106cm/s. The drift velocity of hot carriers saturates as the electric field and the avalanche multiplication factor increase. In the 0.4-μm-thick a-Se HARP target, the relaxation length ratioλE/λand the relaxation time ratioτE/τsaturate as the avalanche multiplication factor increases. In addition, the relaxation length ratioλE/λand the relaxation time ratioτE/τat 1×108V/m were 2.75 and 14.66, respectively.

Excess Electrons and Positive Charge Carriers in Liquid Methane. I

1973 ◽  
Vol 28 (3-4) ◽  
pp. 511-518 ◽  
Author(s):  
George Bakale ◽  
Werner F. Schmidt
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Drift Velocity ◽  
Positive Charge ◽  
Charge Carriers ◽  
Excess Electrons ◽  
Radiation Induced ◽  
Liquid Methane ◽  
Increasing Temperature ◽  
Field Strengths

AbstractThe drift velocities of radiation-induced excess electrons and positive charge carriers in liquid methane were measured at different electric field strengths and several temperatures. For the excess electrons the drift velocity increases up to 1.5 kV cm-1 proportional to the electric field strength and a mobility of (400±50) cm2 V-1 s-1 at T = 111 °K was obtained. Above 1.5 kV cm-1 the drift velocity varies with E½. The temperature coefficient of the mobility is negative. For the positive charge carriers the measurements were carried out up to electric field strengths of 50 kV cm-1 and the drift velocity remained proportional to the field giving a mobility of (2.5 ± 0.5) · 10-3 cm2 V-1 s-1 at 7 = 111 °K. The mobility increased with increasing temperature. The reaction of excess electrons with oxygen was also studied and a rate constant of 8.4 · 1011 l mole-1 s-1 was obtained.

Avalanche Breakdown Luminescence of InGaN/AlGaN/GaN Heterostructures

1997 ◽  
Vol 2 ◽  
Author(s):  
F. Manyakhin ◽  
A. Kovalev ◽  
V.E. Kudryashov ◽  
A.N. Turkin ◽  
A.E. Yunovich
Keyword(s):  
Electric Field ◽  
Short Wavelength ◽  
Reverse Bias ◽  
Impact Ionization ◽  
High Electric Field ◽  
Luminescence Spectra ◽  
Avalanche Breakdown ◽  
Ingan Layer ◽  
Radiation Spectra ◽  
Hot Plasma

Luminescence spectra of InGaN/AlGaN/GaN p-n-heterostructures were studied at reverse bias sufficient for impact ionization. There is a high electric field in the active InGaN-layer, and the tunnel component of the current dominates at the low reverse bias. Avalanche breakdown begins at |Vth|> 8⋄10 V, i.e. ≈3 Eg/e. Radiation spectra have a short wavelength edge 3.40 eV, and maxima in the range 2.60⋄2.80 eV corresponding to the injection spectra. Mechanisms of the hot plasma recombination in p-n-heterojunctions are discussed.

scholarly journals Carrier Transport Properties of GAN in High Electric Field

2019 ◽  
Vol 8 (3S) ◽  
pp. 88-93
Keyword(s):  
Electric Field ◽  
Transport Properties ◽  
Carrier Transport ◽  
Impact Ionization ◽  
Maximum Velocity ◽  
Ionization Rate ◽  
High Electric Field ◽  
Electric Field Increase ◽  
Valence Bands ◽  
The Impact

The Monte Carlo (MC) simulation of the carrier transport mechanisms including impact ionization at high electric field in GaN is presented. Two non-parabolic conduction and valence bands were considered for the simulation of transport properties of electron and hole respectively. The carriers’ drift velocity and energy are simulated as a function of applied electric field at room temperature. The maximum velocity of electron is 2.85 × 107 cm/s at 140 kV/cm. The velocity of electron is saturated at 2 × 107 cm/s at electric field greater than 300 kV/cm. In our work, the velocity of hole is 5 × 106 cm/s at 500 kV/cm. Electron energy increases as the electric field increase and fluctuated at electric field greater than 600 kV/cm when impact ionization occurred. The impact ionization rates are obtained by using modified Keldysh equation. The hole impact ionization rate is higher than that of electron. This work also shows higher electron impact ionization coefficient than that of hole at electric field greater than 4.04 MV/cm

scholarly journals Impact Ionization Phenomenon of TiO2 Rutile (110) under High Electric Field and Its Application

Shinku ◽  
2005 ◽  
Vol 48 (3) ◽  
pp. 175-177
Author(s):  
Hiroshi HASHIMOTO ◽  
Tokuyuki TERAJI ◽  
Toshimichi ITO
Keyword(s):  
Electric Field ◽  
Impact Ionization ◽  
High Electric Field ◽  
Tio2 Rutile
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