This is used to select the part of the experiment to perform 1 magnetic field vs current. The transverse voltage hall effect measured in a hall probe has its origin in the magnetic force on a moving charge carrier. In semiconductors, the charge carriers which produce a current when they move may be positively or negatively charged. Hall effect applications of hall effect electrical4u. Prepare a table that gives the following information. A current can be thought of as a negative charge moving in one direction fig. The hall effect is used extensively to study conduction in materials, particularly in semiconductors. Students will measure hall coefficient and carrier charge concentration in a given semiconductor crystal which will help them to understand important concepts in. Germanium is an indirect bandgap semiconductor with a room temperature. Hall e ect measurements of the carrier density and mobility of a 3d electron gas in a gaasalgaas heterostructure d. First some current 1a is sent through the electromagnet to. And this is used to select the material for finding hall. In solid state physics, hall effect is an important tool to characterize the materials especially semiconductors.
In measuring v h, the following is the accurate method. The determination of the concentration of the charge carriers n or p. In general, the hall voltage is not a linear function of magnetic field applied, i. A current can be thought of as a negative charge moving in one direction or as a positive charge moving in the opposite direction.
The hall effect is when a magnetic field is applied at right angles to the current flow in a thin film where an electric field is generated, which is mutually perpendicular to the current and the magnetic field and which is directly proportional to the product of the current density and the magnetic induction. She hall effect in semiconductor experimentation lab university. Investigating the hall effect in silver objects of the experiment g validation of the proportionality of the hall voltage and the magnetic flux density. We have assumed so far that the mobile charge carriers within solids are electrons and this is in agreement with the sign of the hall voltage for most materials. Thin film samples consisting of a semiconductor inas and two different metals aluminum and gold are investigated to determine the sign and density of the. The temperature range of this experiment is 77k to 400k at its most extreme. Hall effect experiment utk department of physics and. The hall effect is the production of a voltage difference the hall voltage across an electrical conductor, transverse to an electric current in the conductor and to an applied magnetic field perpendicular to the current. The hall effect discovered in 1879 by edwin hall it is the development of a potential difference in a conductor transverse to the current passing. Consider a rectangular conductor of thickness t kept in xy plane. The hall coefficient is calculated based on experimental results and used to measure fundamental semiconductor properties of the given doped sample of.
The crystal is covered by a protective layer of paint. Hall effect measurement in germanium electrical transport option prof. The objective of this educational module is to measure the hall effect germanium and determine the carrier concentration and type as a function of temperature. In this experiment the characteristics of an electromagnet were investigated, and then this electromagnet was used to show that the hall voltage v h is directly proportional to the product of the magnetic. The hall effect was discovered in 1879 by edwin herbert hall while working on his doctoral degree at the johns hopkins university in baltimore, maryland, usa discovered 18. We were supposed to observe the hall effect in semiconductors and measure the hall coefficient rh and find the concentration and type of semiconductor. Semiconductor hall effect basic concepts, numerical on. This arrangement keeps the current flow in the foil spatially uniform. Abstract in order to investigate the nature of charge carriers in electric conductors, we carry out an experiment to measure the hall coecients of silver and tungsten. V hall w is the magnitude of the electric field due to the hall effect. The above argument provides a simple picture in which to think about the hall effect and in fact leads to the correct answer if pursued. In this experiment you will measure the re sistivity and the hall coefficient as functions of the temperature, for an. If a current carrying conductor placed in a perpendicular magnetic field, a potential difference will generate in the conductor which is perpendicular to both. The hall effect experiment determines the sign of the charge carriers in current flow.
Hall was attempting to verify the theory of electron flow proposed by kelvin some 30 years earlier. The importance of the hall effect becomes apparent when semiconductors are used, as we now see. For most metals, there will be a single charge carrier per atom, and n can be calculated using the molar mass and the density of the material. Hall e ect measurements of the carrier density and. California polytechnic state university solid state physics laboratory. To determine which it actually is, the semiconductor is immersed in the magnetic field. Edwin hall in 1879 while he was a doctoral candidate at johns hopkins university in baltimore.
The hall effect experiment using new data acquisition and processing methods 33 figure 6. When a piece of metal or semiconductor is placed in magnetic field, more precisely in transverse magnetic field, and direct current is allowed to pass through it, then the electric field gets developed across the edges of metal or semiconductor specimen. Hall angle 5800560054005200500048004600 100 105 110 115 120 125 5 s temperature k hall mobility the mobility of the carrier expected to decrease with temperature efield from hall effect divided by generated efieldwe expect the e field from the hall effect to decrease with temp causing the hall angle to decrese. Hall effect ndoped semiconductor se7260 products pasco. Binaural beats concentration music, focus music, background music for studying, study music greenred productions relaxing music 231 watching live now. Instrument manuals this lab will be graded 30% on theory, 20% on technique, and 50% on analysis. The hall effect in metals and semiconductors in this experiment, students learn about the classical hall effect which is the basis of most sensors used in magnetic field measurements. A foil current is passed through the sample left to right in the photo via the 5wire harnesses. If a current passes through a conducting material along the x direction and there is a magnetic. The magnetic force is f m ev d b where v d is the drift velocity of the charge. These measurements will enable the student to determine. Hall observed that when a currentcarrying conductor is placed in a transverse magnetic eld, the lorentz force on the moving charges produces a potential di erence perpendicular to both the magnetic eld and the electric current. Significance of the hall effect on semiconductors gulpmatrix.
For clarity, the original effect is sometimes called the ordinary hall effect to distinguish it from other hall effects which have. Work purpose the hall effect is one of the most important effects in the determination of the parameters that characterize from the electrical point of view the semiconductor materials. The hall effect voltage, v h, and hall coefficient, r h, for the same sample will be measured using a magnetic field. Pdf the hall effect experiment using new data acquisition and. Lesson plan hall effect patterson where i is the current, b is the magnetic field in teslas, n is the charge carrier density of the material, q is the fundamental charge, and t is the thickness of the material. Using a microvoltmeter, we are able to make measurements of the hall voltage across a conductor due to an applied magnetic eld. Hall effect measurement in germanium electrical transport.
The hall effect experiment has been used to demonstrate the existence of positive charge carriers in semiconductors. This experiment introduces students to the hall effect which is a fundamental principle of magnetic field sensing. Hall effect is used to calculate the mobility of charge carriers free electrons and holes. I recently performed this experiment in the solid states lab during the ii semester for m. This slider activate only if hall effect setup is selected. Digital voltmeter is much more convenient to use in hall experiment, because. The whole system is mounted in a pen type case for further protection. Pdf the hall effect, in all its variants classic, quantum or fractional quantum, is one of the effects that revolutionized certain areas of physics. The sample is about 25mm square with a thickness of 0. The hall effect and its application in the measurement of. In this experiment, the hall effect will be used to study some of the physics of charge transport in metal and semiconductor samples.
Harsh shukla hall sensor hall effect and its applications hall effect thruster 2. The paper briefly describes the hall effect and its application in semiconductor material analysis. The hall effect experiment conducted by edwin hall in 1879 determines the sign of the charge carriers in current flow. Chiayib stony brook university graduate physics laboratory dated. It directly determines both the sign and density of charge carriers in a given sample. Hall effect applications of hall effect august, 2018 february 24, 2012 by electrical4u whenever we place a current carrying conductor in a magnetic field, there is a deflection of the charge carriers due influence of magnetic field in the conductor body.445 910 865 711 339 559 371 1295 268 1191 626 925 79 447 776 49 478 1242 1334 734 619 668 180 1211 566 132 168 1073 1366 238 1078 998 800 494 786 517 419