Generalized expression for the debye screening length in. An attempt is made to study the effect of carrier degeneracy on the debye screening length of the carriers in tetragonal semiconductors taking degenerate n. A possible source of this discrepancy is that the ferromagnetic contact was not considered in 5. Generalized expression for the debye screening length in semiconductors under the influence of magnetic quantization a. Mukherji institute of radio physics and electronics, university college of science and technology, 92 acharya prafulla chandra road, calcutta 700009, india received 9 april. Mar 24, 2020 debye screening is weaker on the crumpled graphene, potentially enabling a higher sensitivity detection of dna. Debye length is an important parameter in plasma physics, electrolytes, and colloids dlvo theory. Debye length is an important parameter in plasma physics, electrolytes, and. Debye screening length ebook by kamakhya prasad ghatak. Immobilization of antibody causes current gain increase in 1x pbs, and 1% bsa further increase the current gain fig. The following equation is used to evaluate the debye length.
Read debye screening length effects of nanostructured materials by kamakhya prasad ghatak available from rakuten kobo. What is the significance of debye length in drift diffusion modelling. Just enter the term that you would like to have explained and start the search. Nanowire field effect transistors nwfets can serve as ultrasensitive detectors for labelfree reagents.
In order to effectively detect proteins with receptorimmobilized fets, the electrical measurements are usually conducted in diluted buffer solutions, such as in 0. It is found on the basis of the karavaev and borisenko model, which includes all types of anisotropies in the energy spectrum and has recently been demonstrated in the literature to be the most valid model for cd. It is an important part of the behavior of chargecarrying fluids, such as ionized gases classical plasmas, electrolytes, and charge carriers in electronic conductors semiconductors, metals. Jan 03, 2012 beyond the debye length in high ionic strength solution. Spherical conducting probes in finite debye length plasmas. Thus, for optimal sensing, the debye length must be carefully selected for nwfet measurements because molecules binding to the devices are removed from the sensor surface by 212 nm the size of the receptor proteins or dna. General strategy for biodetection in high ionic strength. Mukherji institute of radio physics and electronics, university college of science and technology, 92 acharya prafulla chandra road, calcutta 700009, india received 9 april 1975 the nature of the magnetic. Reconciliation of the conwellweisskopf and brooksherring. Chakravarti institute of radio physics and electronics, university college of science and technology, calcutta. The nwfet sensing mechanism assumes a controlled modification in the local channel electric field created by the binding of charged molecules to the nanowire surface. The gap is much larger than the debye length in 1x pbs 0. Effect of carrier degeneracy on the screening length in. A double layer dl, also called an electrical double layer, edl is a structure that appears on the surface of an object when it is exposed to a fluid.
Dipole scattering in highly polar semiconductor alloys wei zhao and debdeep jena department of electrical engineering, university of notre dame, notre dame, indiana 46556 received 2 march 2004. Temperature dependence of the debye screening length in heavily. Despite subnanometer debye screening lengths, aptamerfets responded to wide ranges of target concentrations 10 14 to 10 9 m in undiluted i. Beyond the debye length in high ionic strength solution. The materials considered are quantized structures of nonlinear optical, iiiv, iivi, ge, te, platinum antimonide, stressed materials, bismuth, gap, gallium antimonide, iiv and bismuth. Volume 53a, number 5 physics letters 14 july 1975 on the oscillatory nature of the debye screening length in degenerate semiconductors under magnetic quantization a. A debye sphere is a volume whose radius is the debye length. Daway from the boundary, the value of the spin current is similar to the one at the charge neutrality condition, provided the spin polarization is the same 5. The debye length is the scale over which mobile charge carriers screen out electric fields in plasmas and other conductors.
Ultrasensitive detection of nucleic acids using deformed. Detection beyond the debye screening length in a high. Jul 12, 2017 the gap is much larger than the debye length in 1x pbs 0. How does the debye length differ from the length of the space. Aptamerfieldeffect transistors overcome debye length. Debye screening length diffusion during d range of long wavelengths of phonons which scatter carriers is determined by debye screening length l d debye screening length n t n 4 0 1 t e n n e 4 n t 0 e t d. Debye length is a measure for the electrostatic screening in plasma, colloids or in a semiconductor material. Debye screening length effects of nanostructured materials. Dipole scattering in highly polar semiconductor alloys wei zhao and debdeep jena department of electrical engineering, university of notre dame, notre dame, indiana 46556. Temperature dependence of the debye screening length in.
Importance of the debye screening length on nanowire field. In the present work, a generalized expression is derived for the debye screening length of the carriers in heavily doped semiconductors having gaussian band. Width of the region close to the pn junction without free carriers. What this means, referring to the picture at right, is that the excess ionic charge within the sphere of radius. Insulators, metals, and semiconductors curt wittig.
Chargedimpurity scattering 1591 dr is the elementary solid angle into which the particle is scattered, and 1, is the debye screening length. This monograph solely investigates the debye screening length dsl in semiconductors and their nanostructures. How does the debye length differ from the length of the. Estimating the debye length the debye length is the distance over which a charge q is shielded by the ions in a solution. The dl refers to two parallel layers of charge surrounding the object. Tsong chen,bc chuhan wang,f cai he,f rui he,f and xuan p. With each debye length, charges are increasingly electrically screened.
Debye screening in singlemolecule carbon nanotube field. In the present work, a generalized expression is derived for the debye screening length of the carriers in heavily doped semiconductors having gaussian bandtails. Lecture 1 definition of a plasma, examples, plasma temperature, debye shielding, plasma criteria duration. One of the original motivations for developing sceptic3d was to study mach probes in tokamak edge plasmas, where the electron debye length. The density of electronic states per unit energy and per unit volume. In physics, screening is the damping of electric fields caused by the presence of mobile charge carriers. In the context of a charged surface in an electrolytic solution, the thickness of the double layer that forms at the charged surface is called the debye length \kappa1. Jan 14, 2016 lecture 1 definition of a plasma, examples, plasma temperature, debye shielding, plasma criteria duration. It is very relevant to determine the stability and the use of surfactants for colloidal solutions and also for the depth profiling technique used to measure the doping profile in semiconductor materials. Careful control of the solution debye length is critical for unambiguous selective detection of macromolecules.
The debye length resulting in any one of these situations thus is nothing but the typical distance needed for screening the surplus charge by the mobile carriers present in the material. In other words, after you moved about one debye length away from the surplus charge, its effects on the mobile charges of the material are no longer felt. Characteristic length over which the carrier density in a semiconductor changes by a factor e. In recent years, considerable efforts have been made in studying the various features of degenerate semiconductors having parabolic and nonparabolic energy.
Spin diffusion and the role of screening effects in. In plasmas and electrolytes, the debye length also called debye radius, named after peter. As you might know, the debye length is a crucial material parameter not only in all. Interestingly, the derivation for the instability criterion assumes quasineutrality, which, as described in the previous section, is not a given for small debye length systems. The materials considered are quantized structures of nonlinear optical, iiiv, iivi, ge, te, platinum antimonide, stressed materials, bismuth, gap, gallium antimonide, iiv and bismuth telluride respectively. Usyd senior plasma physics lectures 44,684 views 9.
Screening limited switching performance of multilayer 2d. Dipole scattering in highly polar semiconductor alloys. The debye length in physiological salt environment 1x pbs is near 0. However, in the case where depletion layer barriers exist adjacent to grain boundaries, the. The temperature dependence of the screening length is also computed for such semiconductors, taking ntype gaas as an example. Debye length case regions 7 and 8 can also be treated in the drift approximation, although to our knowledge no publication taking advantage of this property is available. What is the significance of debye length in drift diffusion.
1156 138 285 1022 1499 424 1198 1532 456 434 1337 1001 201 388 888 1564 465 1219 1313 812 393 144 487 1515 286 386 1470 488 262 1155 436 959 158 493 610 528 542 1030 295 588 1044 1197 1342 113 291 1160 557