Topic
Depletion region
About: Depletion region is a research topic. Over the lifetime, 9393 publications have been published within this topic receiving 145633 citations.
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TL;DR: The first microscopic information on the extent of the space-charge region and its behavior with poling time was reported using secondary ion mass spectrometry to monitor the distribution of charged impurities as discussed by the authors.
Abstract: Applying a dc electric field across a fused silica sample at elevated temperatures followed by cooling the sample with the field applied (thermal poling) leads to a second-order nonlinearity that has been linked to the formation of a space-charge region in bulk glass. The first microscopic information on the extent of the space-charge region and its behavior with poling time is reported using secondary ion mass spectrometry to monitor the distribution of charged impurities. Lithium and sodium ions are observed to form depletion regions. Potassium and sodium ions as well as a hydrogenated species appear to be injected from the surface. The extent of the space-charge region evolves approximately logarithmically with poling time well after the nonlinearity as measured by second-harmonic generation has been established. The evolution of the space charge region can be qualitatively understood by an ion-exchange model that allows interaction of two ionic carriers with vastly different mobilities.
86 citations
IBM1
TL;DR: In this article, the authors studied the transient characteristics of charge collection from alpha-particle tracks in silicon devices, and showed that the field of charge collecting from alpha particle penetration extends far down into the bulk silicon along the length of the alpha particle track and funnels a large number of carriers into the struck junction.
Abstract: We studied the transient characteristics of charge collection from alpha-particle tracks in silicon devices. We have run computer calculations using the finite element method, in parallel with experimental work. When an alpha particle penetrates a pn-junction, the generated carriers drastically distort the junction field. After alpha particle penetration, the field, which was originally limited to the depletion region, extends far down into the bulk silicon along the length of the alpha-particle track and funnels a large number of carriers into the struck junction. After less than one nanosecond, the field recovers to its position in the normal depletion layer, and, if the track is long enough, a residue of carriers is left to be transported by diffusion. The extent of this field funneling is a function of substrate concentration, bias voltage, and the alpha-particle energy.
85 citations
TL;DR: In this article, a numerical device simulation program was used to evaluate the band-gap engineering in CdS/Cu(In,Ga)Se2 solar cells, and the performance of different design concepts was analyzed.
Abstract: Using a numerical device simulation program, the band‐gap engineering in CdS/Cu(In,Ga)Se2 solar cells is examined. The device physics of different design concepts is analysed. Normal band‐gap grading improves performance, especially due to the additional quasi‐electric field, and the analysis showed that the best results are achieved if the grading extends from the highest band‐gap value at the back up to the space charge region. The double grading concept does not yield further improvement, because the front grading—even if located in the space charge region—repels the minority carriers (electrons) away from the CdS interface, and consequently, the fill factor drops significantly. Notch structures in the base also exhibit lower performance than the uniform band‐gap base due to the lower open‐circuit voltage and poorer fill factor. Therefore, the best results are achieved by a normal grading in a Cu(In,Ga)Se2 base from the edge of the space charge region to the back contact.
85 citations
TL;DR: In this paper, the influence of different junction current components (diffusion current for radiative and Auger 7 recombination mechanisms, tunneling and depletion layer currents) on the R 0 A product of n + - p -Hg 1− x Cd x Te photodiodes is considered.
85 citations
TL;DR: In this paper, the effect of large electric fields on the optical absorption coefficient of germanium at room temperature was studied and the experimental results were in fairly good agreement with the theoretical predictions of Franz, Keldysh, and others.
Abstract: By use of the carrier-depleted region of a reverse-biased $p\ensuremath{-}n$ junction, it has been possible to study the effect of large electric fields on the optical absorption coefficient of germanium at room temperature. In the energy range below the edge of the direct interband transitions, the absorption coefficient increases very strongly with field, and the experimental results are in fairly good agreement with the theoretical predictions of Franz, Keldysh, and others. In the region of the indirect transitions, the changes in the absorption coefficient with field oscillate between positive and negative values as a function of energy. This behavior can be related to the phonon-assisted processes first observed by Macfarlane et al.
85 citations