Thermally Stimulated Currents in the Range of Unity Gain Factor

1971 ◽  
Vol 26 (5) ◽  
pp. 819-823
Author(s):  
J. A. Bragagnolo ◽  
G. Dussel ◽  
K. W. Böer ◽  
G. A. Dussel
Keyword(s):  
Space Charge ◽  
Space Charge Region ◽  
Thermal Quenching ◽  
Gain Factor ◽  
Thermally Stimulated Current ◽  
Thermally Stimulated Currents ◽  
Positive Space Charge ◽  
Unity Gain ◽  
Positive Space

Abstract Thermally stimulated current-curves in CdS platelets with slit electrodes change their character when the photoelectric gain-factor increases above one. Here the photocurrent remains essentially frozen-in up to temperatures at which marked thermal quenching sets in. A positive space charge region is assumed to be responsible for the frozen-in photocurrent. A reliable TSC-analysis of the trap distribution can be conducted only for gain factors considerably below one.

scholarly journals Variation of Velocity of Ions in a Magnetized Plasma Sheath for Different Magnetic Field

2020 ◽  
Vol 6 (1) ◽  
pp. 25-29
Author(s):  
B.R. Adhikari ◽  
S. Basnet ◽  
H.P. Lamichhane ◽  
R. Khanal
Keyword(s):  
Magnetic Field ◽  
Space Charge ◽  
Space Charge Region ◽  
Normal Component ◽  
Maximum Amplitude ◽  
Plasma Sheath ◽  
Magnetized Plasma ◽  
Positive Space Charge ◽  
The Magnetic Field ◽  
Positive Space

The kinetic trajectory simulation method has been used to study ion velocity profile in a plasma sheath for varying magnetic field at fixed obliqueness. As the electrons have higher velocity compared to that of ions the wall is charged up negatively with respect to the core plasma. The negative potential then attracts the ions and repels electrons forming a thin positive space charge region in front of the wall. This positive space charge region, known as the ‘sheath’ separates the negatively charged wall from the quasineutral ‘presheath’ plasma. The ions moving towards the wall have to satisfy the Bohm criterion to ensure the stability of the overall plasma. The mean value as well as oscillation frequency of velocity of ions change as the magnetic field is varied from 1.5 to 10.5 mT. The maximum amplitude of normal component of velocity is almost independent of the magnetic field but the maximum amplitude of other components of velocity change and shows oscillating nature as the magnetic field changes.

The structure of the impulse corona in a rod/plane gap I. The positive corona

1970 ◽  
Vol 315 (1520) ◽  
pp. 1-25 ◽  
Keyword(s):  
Spatial Distribution ◽  
Electric Field ◽  
Space Charge ◽  
Negative Ions ◽  
Corona Discharges ◽  
Theoretical Derivation ◽  
Plane Electrode ◽  
Positive Space Charge ◽  
Positive Ion ◽  
Positive Space

The dissipation of space charge following the growth of impulse corona discharges in positive rod/earthed plane gaps has been measured with an electrostatic fluxmeter. A method is described to determine the spatial distribution and magnitude of the space charge together with the associated electric field. Initial positive ion densities of up to 100 μC m -3 have been found. The total positive space charge deposited in a 40 cm gap at 160 kV is 500 nC. Electrons emitted from the plane electrode as a result of corona channels crossing the gap are shown to be trapped in the discharge space as negative ions. The recovery of the gap over several seconds is largely due to ionic drift to the electrodes. A theoretical derivation of the rate of deionization agrees with observed values.

THERMAL CURRENTS FROM UNDOPED SEMI-INSULATING GaAs MONITORED BY CHARGE DEEP-LEVEL TRANSIENT SPECTROSCOPY

1995 ◽  
Vol 09 (23) ◽  
pp. 3099-3114
Author(s):  
I. THURZO ◽  
K. GMUCOVÁ ◽  
F. DUBECKÝ ◽  
J. DARMO
Keyword(s):  
Space Charge ◽  
Space Charge Region ◽  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Energy Levels ◽  
Thermally Stimulated Currents ◽  
Metal Semiconductor Metal ◽  
Transient Spectroscopy ◽  
Electrical Bias

Metal-semiconductor-metal (MSM) devices prepared from crystalline undoped semi-insulating GaAs were investigated by charge deep-level transient spectroscopy (QDLTS), while exciting the devices by electrical bias pulses in dark. Unlike current concepts of the QDLTS response, thermally stimulated currents were integrated from devices with GaAs crystals thinned down to or below 200 µm and equipped with Au electrodes. Au-GaAs-Au structures on 230 µm thick crystals exhibited standard QDLTS response on either cooling or heating between 100 K and 250 K. It is concluded that a macroscopic space charge region of width ≈10−7 m is formed at the Au/GaAs interface, as the dominant energy levels became ionized. Obtained results on the peaks of the thermally stimulated charge were correlated with those of potentially identical peaks observed via optical admittance transient spectroscopy (OATS).

scholarly journals EMERGING TRENDS IN WALL-FREE HALL THRUSTERS DEVELOPMENT

2021 ◽  
pp. 111-116
Author(s):  
I.V. Litovko ◽  
V.Yu. Bazhenov ◽  
A.A. Goncharov ◽  
A.N. Dobrovolsky ◽  
I.V. Naiko
Keyword(s):  
Electric Field ◽  
Space Charge ◽  
Hybrid Model ◽  
Cathode Surface ◽  
Virtual Cathode ◽  
Hall Thrusters ◽  
Positive Space Charge ◽  
Emerging Trends ◽  
New Type ◽  
Positive Space

2D-hybrid model was created for the proposed new type accelerator with a virtual cathode which allows to avoid sputtering of the cathode surface and to preserve the dynamics of accelerated ions. In the framework of the model, it was shown that ions first form a positive space charge in the system center, and eventually, under an ac-tion of created own electric field, emerge from both ends of the system.

Impact of positive space charge depletion layer on negatively charged and neutral centers in gold–diamond Schottky junctions

Carbon ◽  
2019 ◽  
Vol 153 ◽  
pp. 381-388 ◽  
Author(s):  
Kang Liu ◽  
Sen Zhang ◽  
Benjian Liu ◽  
Mingqi Sun ◽  
Jiwen Zhao ◽  
...  
Keyword(s):  
Space Charge ◽  
Depletion Layer ◽  
Positive Space Charge ◽  
Schottky Junctions ◽  
Positive Space ◽  
Charge Depletion
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