Transport Properties of Laser-Generated Non-Equilibrium Plasmas in Semiconductors

Driel, H. M. van

doi:10.1007/978-94-017-1915-5_7

Cited by 4 publications

(2 citation statements)

References 35 publications

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“…The concept of carrier temperature T c is widely used in describing intense photoexcited carriers in semiconductors [1][2][3][4][5][6]. A higher carrier temperature T c than the lattice temperature T L is commonly used to describe a non-equilibrium carrier gas.…”

Section: Discussionmentioning

confidence: 99%

“…The absorption of high-intensity laser pulses by semiconductors leads to the establishment of highly non-equilibrium carrier plasmas [1][2][3][4][5][6]. If the semiconductor is excited with photons of energy hν much lower than the energy bandgap E g of the semiconductor (hν E g ), the carrier heating is due to intraband free-carrier transitions.…”

Section: Introductionmentioning

confidence: 99%

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Experimental study of the hot-carrier impact ionization photovoltaic effect in pulsed-CO₂-laser-excited silicon junctions

Encinas‐Sanz

Marı́n

Guerra

2001

Semicond. Sci. Technol.

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An experimental study has been carried out on the dependence of the hot-carrier highly nonlinear photovoltaic effect induced in silicon n + /p junctions by 10.6 µm laser pulses on the doping level and the carrier density profile. The measured response is optimized by using narrow step junctions and a high doping level n + ≈ 10 20 cm −3 . The main features of the obtained results can be qualitatively interpreted by taking the following into account: conditions for a thermalized hot-carrier plasma, generation rate by impact ionization processes, generated minority diffusion current and recombination and absorption losses.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental study of the hot-carrier impact ionization photovoltaic effect in pulsed-CO₂-laser-excited silicon junctions

Encinas‐Sanz

Marı́n

Guerra

2001

Semicond. Sci. Technol.

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Hot carrier internal thermionic photoemission in pulsed CO/sub 2/-laser-excited n+-p silicon junctions

Encinas‐Sanz

1997

IEEE J. Quantum Electron.

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Signal formation and decay in CdTe x‐ray detectors under intense irradiation

Jahnke

Matz

1999

Medical Physics

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The response of Cd(Zn)Te Schottky and resistive detectors to intense x-rays is investigated in a commercial computed tomography (CT) system to assess their potential for medical diagnostics. To describe their signal height, responsivity, signal-to-noise ratio (SNR), and detective quantum efficiency the devices are modeled as solid-state ionization chambers with spatially varying electric field and charge collection efficiency. The thicknesses and pixel areas of the discrete detector elements are 0.5-2 mm and a few mm2, respectively. The incident spectrum extends from 26 to 120 keV and comprises 10(10) quanta/s cm2. It photogenerates a carrier concentration in the semiconductor that is two to three orders of magnitude above the intrinsic concentration, but remains to a similar extent below the charge densities on the device electrodes. Stable linear operation is achieved with the Schottky-type devices under high bias. Their behavior can be modeled well if negatively charged near-midgap bulk defects with a concentration of 10(11)-10(13) cm-3 are assumed. The bulk defects explain the amount and time constant (about 100 ms) of the detrapping current measured after x-ray pulses (afterglow). To avoid screening by the trapped space charge the bias voltage should exceed 100(V) x [detector thickness/mm]2. Dark currents are of the order of the generation-recombination current, i.e., 300 pA/mm3 detector volume. With proper device design the signal height approaches the theoretical maximum of 0.2 A/W. This high responsivity, however, is not exploited in CT since the SNR is determined here by the incident quantum noise. As a consequence of the detrapping current, the response speed does not meet CT requirements. A medium-term effort for crystal growth appears necessary to achieve the required reduction of the trap density by an order of magnitude. Scintillation based detectors are, therefore, still preferred in fast operating medical diagnostic systems.

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Transport Properties of Laser-Generated Non-Equilibrium Plasmas in Semiconductors

Cited by 4 publications

References 35 publications

Experimental study of the hot-carrier impact ionization photovoltaic effect in pulsed-CO₂-laser-excited silicon junctions

Experimental study of the hot-carrier impact ionization photovoltaic effect in pulsed-CO₂-laser-excited silicon junctions

Hot carrier internal thermionic photoemission in pulsed CO/sub 2/-laser-excited n+-p silicon junctions

Signal formation and decay in CdTe x‐ray detectors under intense irradiation

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Transport Properties of Laser-Generated Non-Equilibrium Plasmas in Semiconductors

Cited by 4 publications

References 35 publications

Experimental study of the hot-carrier impact ionization photovoltaic effect in pulsed-CO2-laser-excited silicon junctions

Experimental study of the hot-carrier impact ionization photovoltaic effect in pulsed-CO2-laser-excited silicon junctions

Hot carrier internal thermionic photoemission in pulsed CO/sub 2/-laser-excited n+-p silicon junctions

Signal formation and decay in CdTe x‐ray detectors under intense irradiation

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Experimental study of the hot-carrier impact ionization photovoltaic effect in pulsed-CO₂-laser-excited silicon junctions

Experimental study of the hot-carrier impact ionization photovoltaic effect in pulsed-CO₂-laser-excited silicon junctions