In general, the thermal conductivity of gases increases with increasing temperature. Retrieved from https://www.thoughtco.com/table-of-electrical-resistivity-conductivity-608499. Magnetic susceptibility of Germanium is . The indium densities, The electrical properties of chemical vapour deposited p-type epitaxial diamond layers are studied in high electric field conditions. The electrical conductivity of pure germanium can be increased by. Low-temperature anomalies in the Hall coefficient and electrical resistivity\char22{}a steep maximum and a change of the slope of the log resistivity versus $\frac{1}{T}$ curve in germanium, The energy levels of ordered impurities in semiconductors are formally equivalent to the energy levels of metallic hydrogen if a number of simplifying approximations are made. We realize that the basics in the materials science can help people to understand many common problems. Thus, EGO is equal to 0.785 (1.21) eV for Ge (Si). The localization length and the hopping parameters in a-Ge are determined using the surface leakage current measured from three high-purity planar Ge detectors. In this paper, the electrical conductivity of a nondegenerate electron gas with a complex shaped quantum well is calculated. The electrical and thermal conductivities of metalsoriginate fromthe fact that theirouter electrons are delocalized. Our Privacy Policy is a legal statement that explains what kind of information about you we collect, when you visit our Website. Bell, Terence. In fact, for crystalline, nonmetallic solids such as diamond, kphcan be quite large, exceeding values of k associated with good conductors, such as aluminum. Conductivity sensors for water bodies measure from a few micro-siemens per cm (S/cm) to about 200 milli-siemens per cm (mS/cm). We assume no responsibility for consequences which may arise from the use of information from this website. An intrinsic semiconductor is just a pure semiconductor without any significant defects or external impurities.The electrical conductivity of intrinsic semiconductors depends strongly on temperature.At absolute zero (T = 0 K T = 0\ \rm K T = 0 K), semiconductors behave like insulators.However, as we increase the temperature, the electrons in the conduction band gain thermal energy and jump . The law, named afterGerman physicist Georg Ohm, appeared in 1827 in a published paper laying out how current and voltage are measured via electrical circuits. Zirconium. Electrical resistivity, represented by the Greek letter (rho), is a measure of how strongly a material opposes the flow of electric current. For nonmetallic solids,kis determined primarily bykph, which increases as the frequency of interactions between the atoms and the lattice decreases. 30, Issue 2. Growth 352, 43 (2012), G. Yang, J. Govani, H. Mei et al., Cryst. *Note: The resistivity of semiconductors (metalloids) is heavily dependent on the presence of impurities in the material. Cells, 1.5 V, with holders, 3 Lamp in holder, 6 V 3 W approx Mounted slice of germanium, see technical note [1977]). Phys. The results are thus of the same form as reported by Lark-Horovitz. Complete step-by-step solution Given . Convert between Electrical Resistivity Units. 1) You may use almost everything for non-commercial and educational use. Because valence electrons are free to move, they can travel through the lattice that forms the physical structure of a metal. Fluidsare a subset of the phases of matter and includeliquids,gases, plasmas and, to some extent, plastic solids. Department of Physics, The University of South Dakota, Vermillion, SD, 57069, USA, Gang Yang,Kyler Kooi,Guojian Wang,Hao Mei,Yangyang Li&Dongming Mei, You can also search for this author in The observed critical Geld at 298 K beyond which p varies as E & is 900 volts/cm for n-type. Anyone canbe able to come here,learn the basicsofmaterials science, material properties and to compare these properties. This article provides an overview. Part of Springer Nature. An approximate, Measurements of conductivity and Hall effect from 11\ifmmode^\circ\else\textdegree\fi{}K to 300\ifmmode^\circ\else\textdegree\fi{}K on a set of $n$-type germanium samples covering the range from, The data of E. J. Ryder on the mobility of electrons in electric fields up to 40,000 volts per cm are analyzed. The calculated results show that the ionized carrier concentration increases with increasing temperature due to thermal excitation, but it reaches saturation around 40K for the single-crystal samples and 70K for the polycrystalline samples. Conductors are made of high-conductivity materials such as metals, in particular copper and aluminium. Metalsin general havehigh electrical conductivity,high thermal conductivity, and high density. She has taught science courses at the high school, college, and graduate levels. On the other hand, ice (solid H2O) is a molecular compound whose molecules are held together by hydrogen bonds, which is effectively a strong example of an interaction between two permanent dipoles. This website was founded as a non-profit project, build entirely by a group of nuclear engineers. The SI unit of electrical resistivity is the ohm-metre (m). Mobility The mobility of a charge varies as T-m over temperature range of 100 to 400 K. For Ge, m = 1.66 (2.33) for electron (hole), For Si, m = 2.5 (2.7) for electron (hole). "Electrical Conductivity of Metals." . (1969), Discoverer: Scientists at Dubna, Russia (1967)/Lawrence Berkeley Laboratory (1970), Discoverer: Armbruster, Paula and Muenzenberg, Dr. Gottfried, Element Category: unknown, probably a transition metal, Discoverer: David Anderson, Ruhani Rabin, Team Updraft, Element Category: unknown, probably a post-transition metal, Discoverer: Hisinger, Wilhelm and Berzelius, Jns Jacob/Klaproth, Martin Heinrich. Haller, IEEE Trans. Total electronic thermal conductivity in n-type germanium as a function of temperature. (Residual Resistivity Ratio) which correlates the thermalresistivity and electrical resistivity as the impurity effect and is primarily additive in resistivity. The dashed line has been computed from equation (1). This is the case in the most conductive metals, such as silver, gold, and copper. The information contained in this website is for general information purposes only. Electrical Conductivity of Metals. In n-type semiconductor pn << nn. Electrical conductivity of high-purity germanium crystals at low temperature. Hence for n-type semiconductor. -05 ii: SAMPLE OHM-CM 3 5 3 1100 1000 900 800 -K FIG. They have an energy gap less than 4eV (about 1eV). In the case of Germanium the electrical conductivity is 1.45e-8 10^6/cm ohm. Hence. The heat transfer characteristics of a solid material are measured by a property called the thermal conductivity, k (or ), measured in W/m.K. Measurement and modeling of cavity electrical properties elucidated surface electronic states and indicated a potential for controlled electrical isolation in devices. This work was supported by DOE DE-FG02-10ER46709, NSF OISE-1743790, NSF OIA-1738632 and the state of South Dakota. Hansen, E.E. 992, 406 (1955), R. Wichner, S.P. 1 m = 10-2-2-1 foot; Electrical Resistance in a Wire. Dense gases such as xenon and dichlorodifluoromethane have low thermal conductivity. Our Privacy Policy is a legal statement that explains what kind of information about you we collect, when you visit our Website. "Electrical Conductivity of Metals." 4. Liquids tend to have better thermal conductivity than gases, and the ability to flow makes a liquid suitable for removing excess heat from mechanical components. At temperatures near room temperature, the temperature dependence of the conductivity fo intrinsic germanium is found to equal: -E o =C (T 3/2' )exp 2kT where C is a temperature-independent constant and T is in Kelvins. Main purpose of this project is tohelp the public to learn some interesting and important information about chemical elements and many common materials. Therefore, many insulating materials (e.g.polystyrene) function simply by having a large number ofgas-filled pocketswhichprevent large-scale convection. In physics, afluidis a substance that continually deforms (flows) under an applied shear stress. . One siemens is equal to the reciprocal of one ohm. Germanium: 4.6 10-1: 2.17: Glass: 10 10 10 to 10 10 14: 10-11 to 10-15: Gold: 2.44 10-8: . Lu, J.D. Electrical resistance is expressed in Ohms. Under an electric field, free electrons move through the metal much like billiard balls knocking against each other, passing an electric charge as they move. In theperiodic table of elements, the element with the lowest boiling point is helium. if a donar impurity atoms are added to the extent to one part in ( 10) 6 germanium atoms at room temperature. A 113(1), 207 (2014), J.Y.M. Apparatus and Materials. The heat transfer characteristics of a solid material are measured by a property called the thermal conductivity, k (or ), measured in W/m.K. Metalsin general havehigh electrical conductivity,high thermal conductivity, and high density. (The temperature coefficient of resistance of many pure metals is close to 0.004 K-1, so the resistance-temperature graph will extrapolate back to 1/0.004 = 250 K.) You could link this to the idea that the resistance of a pure metal at room temperature is dominated by the vibration of ions, and this will reduce to zero close to 0 K. Anderson, N. Apsley, Semicond. The symbol of resistivity is usually the Greek letter (rho). A liquid in a partial vacuum has a lower boiling point than when that liquid is at atmospheric pressure. Assume Eg=0.67 eV and room-temperature (298 K) Thus, at room temperature in Ge (Si), one atom out of about 10 9 (10 12) contributes one electron-hole pair through breaking of covalent bond.. On the other hand, water boils at 350C (662F) at 16.5 MPa (typical pressure of PWRs). Open Access Article This Open Access Article is licensed under a Creative Commons Attribution 3.0 Unported Licence Density, surface tension, electric conductivity, and speed of sound of sodium dodecanoate (sodium laurate) aqueous solutions have been determined. The mobility decreases many fold due to the influence of scattering by optical modes, By clicking accept or continuing to use the site, you agree to the terms outlined in our. The temperature dependence of electrical conductivity of single-crystal and polycrystalline high-purity germanium (HPGe) samples has been investigated in the temperature range from 7 to 100K. The conductivity versus inverse of temperature curves for three single-crystal samples consist of two distinct temperature ranges: a high-temperature range where the conductivity increases to a maximum with decreasing temperature, and a low-temperature range where the conductivity continues decreasing slowly with decreasing temperature. The coolants used in nuclear reactors include water or liquid metals, such as sodium or lead. C, Particles and Fields. ThoughtCo, Aug. 27, 2020, thoughtco.com/table-of-electrical-resistivity-conductivity-608499. 1. - the resistivity depends strongly on the temperature of the material. Tax calculation will be finalised during checkout. Thethermal conductivity of gasesis directly proportional to the density of the gas, the mean molecular speed, and especially to themean free pathof molecule. The lower the resistivity, the more readily the material permits the flow of electric charge. Alternation of gas pocket and solid material causes that the heat must be transferred through many interfaces causing rapid decrease in heat transfer coefficient. Whereas in the case of conductors, when the temperature increases its resistivity increases as electrons collide more frequently with vibrating atoms. As can be seen, theboiling pointof a liquid varies depending upon the surrounding environmental pressure. These elements, along with the chemically similar elements scandium and yttrium, are often collectively known as the rare earth elements. In particular, diamond has the highest hardness and thermal conductivity (k = 1000 W/m.K) of any bulk material. Discoverer: Priestley, Joseph and Scheele, Carl Wilhelm, Discoverer: Ramsay, William and Travers, Morris, Discoverer: Ramsay, Sir William and Strutt, John (Lord Rayleigh), Discoverer: Del Rio, Andrs Manuel (1801) and Sefstrm, Nils Gabriel (1830), Discoverer: Lecoq de Boisbaudran, Paul-mile, Discoverer: Ramsay, Sir William and Travers, Morris, Discoverer: Bunsen, Robert Wilhelm and Kirchhoff, Gustav Robert, Discoverer: Perrier, Carlo and Segr, Emilio, Discoverer: Reich, Ferdinand and Richter, Hieronymus, Discoverer: Mller von Reichenstein, Franz Joseph, Discoverer: Ramsay, William and Travers, Morris William, Discoverer: Kirchhoff, Gustav and Bunsen, Robert. 175, 23 (1986), G.E. 2. Both the mobility and are positive quantities and are constant for a given material upto electrical fields of about 105 volts/meter. al. However, in other classes of materials, known as semiconductors (e.g. Conduction in metals must follow Ohm's Law, which states that the current is directly proportional to the electric field applied to the metal. Bell, Terence. Solids are similar to liquids in that both are condensed states, with particles that are far closer together than those of a gas. 18-39 18.35 This problem asks that we estimate the temperature at which GaAs has an electrical conductivity of 1.6 x 10-3 (-m)-1 assuming that the conductivity has a temperature dependence as shown in Equation 18.36. Thus, at room temperature in Ge (Si), one atom out of about 109 (1012) contributes one electron-hole pair through breaking of covalent bond. While resistivity is a material property, resistance is the property of an object. Hence. Discoverer: McMillan, Edwin M. and Abelson, Philip H. Discoverer: Glenn T. Seaborg, Joseph W. Kennedy, Edward M. McMillan, Arthur C. Wohl, Discoverer: Glenn T. Seaborg, Ralph A. James, Leon O. Morgan, Albert Ghiorso, Discoverer: Glenn T. Seaborg, Ralph A. James, Albert Ghiorso, Discoverer: Stanley G. Thompson, Glenn T. Seaborg, Kenneth Street, Jr., Albert Ghiorso, Discoverer: Stanley G. Thompson, Glenn T. Seaborg, Bernard G. Harvey, Gregory R. Choppin, Albert Ghiorso, Discoverer: Albert Ghiorso, Glenn T. Seaborg, Torbrn Sikkeland, John R. Walton, Discoverer: Albert Ghiorso, Torbjrn Sikkeland, Almon E. Larsh, Robert M. Latimer, Copyright 2023 Periodic Table | All Rights Reserved |. Correspondence to Step 1: Classification of elements. Mercury. In solid-state physics, this energy gap or band gap is an energy range between valence band and conduction band where electron states are forbidden. The regularity of the lattice arrangement has an important effect onkph, with crystalline (well-ordered) materials likequartzhaving a higher thermal conductivity than amorphous materials like glass. For n-type silicon: Relation Between Line Voltage and Phase Voltage in Delta Connection, Relation Between Line Voltage and Phase Voltage in Star Connection, Charge Densities in Extrinsic Semiconductor, Kirchhoffs Voltage Law Examples with Solution, Kirchhoff's Voltage Law Examples with Solution, Superposition Theorem Example with Solution, Induced EMF | Statically and Dynamically Induced EMF, Reciprocity Theorem Example with Solution, Transient Response in Series RC circuit having D.C. Excitation (First Order circuit). The dissociation energies for Si-H and Ge-H surface monohydride bonds were determined, showing that H chemisorption on Si is energetically stable with respect H{sub 2} gas whereas H chemisorption on Ge is not. Light gases, such ashydrogenandheliumtypically havehigh thermal conductivity. To understand the difference betweenmetals,semiconductorsandelectrical insulators, we have to define the following terms from solid-state physics: This website was founded as a non-profit project, build entirely by a group of nuclear engineers. Maybe add your school logo, work team or anything else to make your paper look cool? The quasi-static current-voltage characteristics have been, Currentvoltage characteristics of polycrystalline silicon films highly doped with phosphorus and boron were studied over a wide range of temperatures (40300 K) and applied electric fields (up to 5, A novel breakdown (BD) mechanism of shallow impurity (SI) under the electric field at low temperatures is suggested for nGaAs samples with the donor concentrations 1014cm3ND1016cm3 and the, The 6eld dependence of mobility has been determined for electrons and holes in both germanium and silicon. Carbon is an insulator with a very low conductivity. Alternation of gas pocket and solid material causes that the heat must be transferred through many interfaces causing rapid decrease in heat transfer coefficient. Summary The idea of conduction by electrons in the energy bands of an impurity system is examined. Light gases, such ashydrogenandheliumtypically havehigh thermal conductivity. For example, sodium chloride (NaCl) is an ionic compound that consists of a multitude of strong ionic bonds. Thethermal conductivityof most liquids and solids varies with temperature. The heat can be removed by channeling the liquid through a heat exchanger. - Materials Science in Semiconductor Processing, https://doi.org/10.1007/s00339-018-1803-2, Germanium: From the first application of Czochralski crystal growth to large diameter dislocation-free wafers, https://doi.org/10.1016/j.mssp.2006.08.002, https://doi.org/10.1080/00018738100101357, Origin and Control of the Dominant Impurities in High-Purity Germanium, The drift mobility of electrons and holes in germanium at low temperatures, https://doi.org/10.1016/0022-3697(60)90151-7, Electrical Properties of Germanium Semiconductors at Low Temperatures, Drift Mobilities in Semiconductors. A liquid at high pressure has a higher boiling point than when that liquid is at atmospheric pressure. https://www.thoughtco.com/electrical-conductivity-in-metals-2340117 (accessed March 4, 2023). Using the electron and hole mobilities for silicon in Table $18.3,$ compute the electron concentration. If a single ball strikes multiple other balls, each of those will carry only a fraction of the energy. and an insulator, such as glass. So, although they can conduct electricity, they are inefficient at the task. Price excludes VAT (USA) Google Scholar, E.E. Authors: Yang, Gang; Kooi, Kyler; Wang, Guojian; Mei, Hao; Li, Yangyang; Mei, Dongming Award ID(s): 1738632 Publication Date: 2018-05-01 NSF-PAR ID: 10063257 Journal . Pure germanium is known to be a semiconductor and has an appearance that is the same as silicon. Cavities were formed in Si and Ge by He ion implantation and annealing, and resultant chemical and electrical properties were investigated. K). The passage takes place with negligible changes in carrier mobility. Transport of thermal energy in solids may be generally due to two effects: Copyright 2023 Periodic Table | All Rights Reserved |, Zinc Boiling Melting Point Thermal Conductivity Expansion, Arsenic Boiling Melting Point Thermal Conductivity Expansion. Discoverer: Scientists at Dubna, Russia (1964)/Albert Ghiorso et. per cm 3. The transfer of energy is strongest when there is little resistance. Themelting pointis the temperature at which the disruptive vibrations of the particles of the solid overcome the attractive forces operating within the solid. Demonstration. It is a measure of a substance's ability to transfer heat through a material by conduction. Most recent implementations of low-cost electrical conductivity (EC) sensors intended for water quality measurements are based on simple two-pole designs. Assume that only one electron of each atom takes part in conduction process. For these materials, the area and volumetric thermal expansion coefficient are, respectively, approximately twice and three times larger than the linear thermal expansion coefficient (V= 3L). 23, Issue 1, Journal of Physics and Chemistry of Solids, Vol. The mean free path also depends on the diameter of the molecule, with larger molecules more likely to experience collisions than small molecules, which is the average distance traveled by an energy carrier (a molecule) before experiencing a collision. Nucl. The table above is based on 20 o C reference.. Mean energy of hole as a function of electronic field F at different lattice temperatures. In particular, diamond has the highest hardness and thermal conductivity (k = 1000 W/m.K) of any bulk material. It is shown that , which lies in the band gap region . Elements Electrical Conductivity Reference Table. (auth). Accordingly, transport of thermal energy may be due to two effects: The unique feature of metals as far as their structure is concerned is the presence of charge carriers, specificallyelectrons. Temperature changes in a substance also mean a changes in conductivity. Themelting pointalso defines a condition in which the solid and liquid can exist in equilibrium. For all practical purposes in a p-type semiconductor at room temperature, the conductivity term from the electron concentration . The density of carriers in the doped semiconductor (10 16 cm-3) is much higher than in the undoped material (~10 10 cm-3), so the conductivity is also many orders of magnitude higher. Electric conductivity may be represented by the Greek letter (sigma), (kappa), or (gamma). Table of Electrical Resistivity and Conductivity. Semiconductors have conductivity in the intermediate range. 9, 437 (2006), Article For vapors, it also depends upon pressure. Rev. Calculate the mobility of electrons. Yang, G., Kooi, K., Wang, G. et al. Where Qvn (Qvp) is the volume charge density of electrons (holes) per cubic meter. Mobility and are expressed in meter2/volt-second. ENGINEERING PHYSICS -SEMICONDUCTING MATERIALS PROBLEMS KEYS. Substances in which electricity can flow are called conductors. Semantic Scholar extracted view of "The low temperature electrical conductivity of n-type germanium" by S. Koenig et al. Thermal expansion is common for solids, liquids and for gases. In solids, atoms vibrate about their equilibrium positions (crystal lattice). Proc. 36.28%. 4. from ionizing radiation) to cross the band gap and to reach the conduction band. The internal consistency of the parameters in the carriers (electrons, normal holes, and light holes) is also shown. 4. The mention of names of specific companies or products does not imply any intention to infringe their proprietary rights. GaAs transistor was first introduced in the year of 1970. Unlike the resistors, the resistivity of the various semiconductors decreases . On combining equations (2) and (6) we get, Where is the mobility of holes (electron) and equals. The electrical conductivity of pure germanium can be increased by (a) increasing the temperature (b) doping acceptor impurities . (2- sentences) As was written, in liquids, the thermal conduction is caused by atomic or molecular diffusion, but physical mechanisms for explaining the thermal conductivity of liquids are not well understood. al. Up to date, curated data provided by Mathematica 's ElementData function from Wolfram Research, Inc. The electrical conductivity vs T of all samples is presented in Fig. The Cookies Statement is part of our Privacy Policy. (auth), Contribution to the Change of the Electrical Properties of Silicon and Germanium Diodes by Neutron Irradiation; ZUR AENDERUNG DER ELEKTRISCHEN EIGENSCHAFTEN VON SILIZIUM- UND GERMANIUM-DIODEN BEI NEUTRONEN-BESTRAHLUNG, RADIATION DAMAGE AS A METHOD FOR STUDY OF ELECTRICAL CONDUCTIVITY, HALL- COEFFICIENT AND THERMOELECTRIC POWER OF GERMANIUM AS FUNCTIONS OF CARRIER CONCENTRATION, ELECTRICAL CONDUCTIVITY CHANGES OF n-TYPE GERMANIUM BOMBARDED BY REACTOR FAST NEUTRONS. Notes on the properties of Germanium: Brinell Hardness: converted from Mohs scale. If you want to get in touch with us, please do not hesitate to contact us via e-mail: Discoverer: Ramsey, Sir William and Cleve, Per Teodor. Hansen, G.S. E. Discoverer: De Marignac, Charles Galissard, Discoverer: De Marignac, Jean Charles Galissard, Discoverer: Ghring, Otto and Fajans, Kasimir. From the room temperature (298 K) conductivity [10-6 (-m)-1] and band gap energy (1.42 eV) of Table 18.3 we determine the value of C (Equation 18.36) by taking natural . , title={The low temperature electrical conductivity of n-type germanium}, author={S H Koenig and G. Robert Gunther-Mohr}, journal={Journal of Physics and Chemistry of Solids}, year={1957 . Therefore higher temperatures implygreater distancebetween atoms. Thethermal conductivityof gases and liquids is therefore generally smaller than that of solids. Resistivity is the opposite of electrical conductivity, evaluating how strongly a metal opposes the flow of electric current. Also as the conductivity of extrinsic semiconductor is more than that of intrinsic semiconductor, thus the conductivity of pure germanium increases by doping Ge crystal either with . In physics, a fluid is a substance that continually deforms (flows) under an applied shear stress. Any addition of thermal energy results in a phase transition. Resistivity is often represented by the Greek letter rho (). Nucl. The authors would like to thank the members of the crystal growth group at The University of South Dakota. and Gay-Lussac, L.-J. Helmenstine, Anne Marie, Ph.D. "Table of Electrical Resistivity and Conductivity." Question: At temperatures near room temperature, the temperature dependence of the conductivity for intrinsic germanium is found to equal Eg o = CT-3/2 exp p 2kT where Cis a temperature-independent constant and I is in Kelvins. The pressure at which vaporization (boiling) starts to occur for a given temperature is called thesaturation pressure. If it is not isometric, there may be different expansion coefficients for different crystallographic directions, and the crystal will change shape as the temperature changes. Unlike gases or liquids, solid materials tend to keep their shape when undergoing thermal expansion. These elements, along with the chemically similar elements scandium and yttrium, are often collectively known as the rare earth elements. The mean free path also depends on the diameter of the molecule, with larger molecules more likely to experience collisions than small molecules, which is the average distance traveled by an energy carrier (a molecule) before experiencing a collision. it passes through a minimum. Due to its low conductivity, it is deemed unsuitable for use in electronic devices. Specific Heat: Value given for solid phase. Phys. Gang Yang. The temperature dependence of electrical conductivity of single-crystal and polycrystalline high-purity germanium (HPGe) samples has been investigated in the temperature range from 7 to 100 K. Dense gases such as xenon and dichlorodifluoromethane have low thermal conductivity. Engineering Electrical Engineering 2. If you continue to use this site we will assume that you are happy with it. The liquid can be said to be saturated with thermal energy. The key variable in applying Ohm's Law is a metal's resistivity. Report No. Class 12. The vibrations of atoms are not independent of each other, but are rather strongly coupled with neighboring atoms. Drift velocity v d as a function of temperature for electric field F=10 4 (V cm-1). Our Website follows all legal requirements to protect your privacy. Liquids tend to have better thermal conductivity than gases, and the ability to flow makes a liquid suitable for removing excess heat from mechanical components. 965, 1126 (1954), E.G.S. The intrinsic semiconductor has a very small conductivity. Wang, W.C. Xiang et al., J. Cryst. 23, Issue 4, Semiconductor Science and Technology, Vol. But refining process of silicon is much more complicated and expensive than that of germanium. Adding a heat will convert the solid into a liquid with no temperature change. Extrinsic semiconductors. It is usually expressed as a fractional change in length or volume per unit temperature change. >> Energy Bands. - the resistivity depends strongly on the presence of impurities in the material.