Measurement of the velocity of current filaments in optically triggered, high gain GaAs switches

The spontaneous radiation energy of the current filaments in high gain GaAs photoconductive semiconductor switches (PCSS) is quantificationally analyzed. The spontaneous radiation formula of the current filaments was derived. The concept of the distribution function of the radiation intensity dependent on radiation wavelength was first introduced in GaAs samples. The radiative recombination coefficients of four peak wavelengths were estimated by the statistical-physical method in high gain GaAs PCSS. Calculated according to the radiative recombination coefficient of 890 nm radiation, the spontaneous radiation energies are consistent with the experimental observations. This explains the observations about optical output energy versus filament current.

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Carrier Injection in High Gain GaAs Photoconductive Semiconductor Switches

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.941-944.602 ◽

2014 ◽

Vol 941-944 ◽

pp. 602-605

Author(s):

Li Zheng ◽

Hong Liu

Keyword(s):

Impact Ionization ◽

High Gain ◽

Electron Avalanche ◽

Carrier Injection ◽

Carrier Generation ◽

Semiconductor Switches ◽

Current Filaments ◽

The Impact ◽

Photo Ionization

The carrier injection in high gain semi-insulating GaAs photoconductive semiconductor switches (PCSS) is studied. A great quantity of carrier generation in the insulating region of the GaAs PCSS depends upon photo-ionization and impact ionization. The impact ionization avalanche carrier generation exists in the electron avalanche domains (EAD). The EAD is closely related to the growing domains associated with carrier injection. Carriers are injected either at the contacts (Cathode and Anode) or at the tip of the current filaments which works as a “contact reaching further into the gap”. Carrier injection plays an important role for the EAD formation.

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Photoionization in GaAs Photoconductive Semiconductor Switches

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.941-944.631 ◽

2014 ◽

Vol 941-944 ◽

pp. 631-634

Author(s):

Hong Liu ◽

Li Zheng ◽

Wei Yang ◽

Xiao Qian Wang ◽

Song Hui Dai ◽

...

Keyword(s):

Carrier Density ◽

Dominant Role ◽

High Gain ◽

Average Density ◽

Maximum Density ◽

Distribution Characteristics ◽

Key Factors ◽

Current Filament ◽

Semiconductor Switches ◽

Current Filaments

The density distribution characteristics of non-equilibrium carrier from spontaneous emission ahead of the tip of the current filaments in high gain semi-insulating GaAs photoconductive semiconductor switches are analyzed. The results show that the ratio of volume to area of the current filament and the average carrier density in the current filaments are two key factors that affect the photoionization effects of the current filaments. The reabsorption of wavelengths λ ≤ 876 nm radiations plays a dominant role in producing the maximum carrier density. The maximum density of photo-generated carrier is approximately 1~3 orders of magnitude lower than the average density of excess carrier inside the current filaments.

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Fiber-optic Control Of Current Filaments In High Gain Photoconductive Semiconductor Switches

10.1109/modsym.1994.597057 ◽

2005 ◽

Cited By ~ 6

Author(s):

F.J. Zutavern ◽

G.M. Loubriel ◽

W.D. Helgeson ◽

M.W. O'Malley ◽

R.R. Gallegos ◽

...

Keyword(s):

Fiber Optic ◽

High Gain ◽

Semiconductor Switches ◽

Current Filaments

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Effect of energy filtering on micro-diffraction in the SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010017075x ◽

1994 ◽

Vol 52 ◽

pp. 604-605

Author(s):

James F. Mancuso ◽

Leo A. Fama ◽

William B. Maxwell ◽

Jerry L. Lehman ◽

Hasso Weiland ◽

...

Keyword(s):

Detection Efficiency ◽

Ccd Camera ◽

High Gain ◽

Microchannel Plate ◽

Electrostatic Energy ◽

Energy Filtering ◽

Electron Channelling ◽

Low Energy Electrons ◽

Low Sensitivity ◽

Angular Field Of View

Micro-diffraction based crystallography is essential to the design and development of many classes of ‘crafted materials’. Although the scanning electron microscope can provide crystallographic information with high spatial resolution, its current utility is severely limited by the low sensitivity of existing diffraction techniques (ref: Dingley). Previously, Joy showed that energy filtering increased contrast and pattern visibility in electron channelling. This present paper discribes the effect of energy filtering on EBSP sensitivity and backscattered SEM imaging.The EBSP detector consisted of an electron energy filter, a microchannel plate detector, a phosphor screen, optical coupler, and a slow scan CCD camera. The electrostatic energy filter used in this experiment was constructed as a cone with 5 coaxial electrodes. The angular field-of-view of the filter was approximately 38°. The microchannel plate, which was the initial sensing component, had high gain and had 50% to 80% detection efficiency for the low energy electrons that passed through the retarding field filter.

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Equivalent Noise Dose Obtained Through Hearing Aids in the Classrooms of Hearing-Impaired Children

Language Speech and Hearing Services in Schools ◽

10.1044/0161-1461.2103.147 ◽

1990 ◽

Vol 21 (3) ◽

pp. 147-150

Author(s):

Ronald A. Wilde

Keyword(s):

Hearing Aids ◽

High Gain ◽

Hearing Impaired ◽

Deaf Children ◽

Impaired Children ◽

Very High ◽

Hearing Impaired Children

A commercial noise dose meter was used to estimate the equivalent noise dose received through high-gain hearing aids worn in a school for deaf children. There were no significant differences among nominal SSPL settings and all SSPL settings produced very high equivalent noise doses, although these are within the parameters of previous projections.

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