Hall effect hall effect in conductor, ntype semiconductor. The hall effect in a metal and a ptype semiconductor required background reading tipler, chapter 10, pages 478479 on the hall effect prelab questions 1. 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 years before the electron. To explain hall effect, consider a sample of a block of conductor of length l, width d and thickness t, through which electric current i is supplied along xaxis as shown in figure 1. Pdf simple notes on hall effect nishad tn academia.
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. In this experiment you will measure the re sistivity and the hall coefficient as functions of the temperature, for an. The hall effect offered the first real proof that electric currents in metals are carried by moving electrons, not by protons. Arriving at the classroom filled with a crowd of young students, oersted placed on the lecture table his. 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. Aug, 20 basic concepts, numerical on hall effect, hall coefficient, numerical on hall coefficient, applications of hall effect. The hall effect and its application in the measurement of.
Hall effect and its applications in semiconductorsphysics about. The difference of potential produced is called the hall emf. Carrier density and mobility can also be calculated. This laboratory manual is based on a manual for a very similiar experiment from the physics.
Ph 3455mse 3255 the hall effect in a metal and a ptype. 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. As a result, the potential difference is developed between the upper and bottom surface of the ntype semiconductor. The hall effect, which was discovered in 1879, determines the concentration and type negative or positive of charge carriers in metals, semiconductors, or insulators. Anomalous hall effect in ferromagnetic semiconductors. If static electricity did not affect magnets in any way, maybe things. Macdonald 1department of physics, the university of texas, austin, texas 78712. Hall effect in semiconductors request pdf researchgate. However, this information can be obtained from hall effect measurements, which are a basic tool for the determination of mobilities. In semiconductors, the charge carriers which produce a current when they move may be positively or negatively charged. Introduction in 1879 edwin hall, a graduate student at johns hopkins university, observed that when a magnetic field is applied at right angles to the direction of current flowing in a conductor, an electric field.
Significance of the hall effect on semiconductors gulpmatrix. The hall effect theory for a charge moving in a magnetic field, it experiences a force acting at right angles to both its direction and the direction of the. When a current carrying semiconductor is placed in a magnetic field, the charge carriers experience force in the direction which is perpendicular to the flow of current and magnetic field, which results in development of voltage. Nov 14, 2016 an effect when occurring when a current carrying conductor is placed in a magnetic field and orientated so that the field is at right angles to the direction of the current. In the presence of a magnetic field b 0 along the zdirection, the holes will experience a force the lorentz force driving them towards the bottom of the sample as shown in figure 1. Hall coe cient is a parameter that measures the magnitude of the hall e ect in the sample. The paper briefly describes the hall effect and its application in semiconductor material analysis. Motivations in this work, we study intrinsic spin hall effect in semiconductors and metals by performing ab initio calculations. In general, the method is used in conjunction with a conductivity measurement to also determine the mobility ease of movement of the charge carriers.
Observation of the spin hall effect in semiconductors. 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. Hall effect semiconductors and its applications engineering physics 1. Hall effect consider the sample of ptype semiconductor with current density j x flowing in the xdirection. These measurements will enable the student to determine. An effect when occurring when a current carrying conductor is placed in a magnetic field and orientated so that the field is at right angles to the direction of the current. Hall measurements can tell us whether a semiconductor is ntype or ptype from the polarity. We report on the optical detection of the spin hall effect in thin films of the semiconductors gaas and ingaas. Hall semiconductor resistance, band gap, and hall effect. The hall effect studies also assumed importance because of an anomaly observed between the sign of the charge carriers indicated by hall coefficient and s in amorphous semiconductors. However, this information can be obtained from hall effect measurements, which are basic tools for the determination of mobilities.
The hall effect is the production of avoltage difference the hall voltage across an electrical conductor, transverse to an electric current in the conductor and a magnetic fi. Hall effect hall effect derivation electronics tutorials. Hall effect in semiconductors look major reference. The hall effect is a galvanomagnetic effect, which was. Semiconductor hall effect basic concepts, numerical on hall. The hall effect and the conductivity of semiconductors 1. Ab initio calculations and model studies a talk in institute of physics, nctu, june 21, 2007. Harsh shukla hall sensor hall effect and its applications hall effect thruster 2. This laboratory manual is based on a manual for a very similiar experiment from the physics 111 advanced undergraduate laboratory at uc. 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.
V is velocity of electrons at right angle to magnetic field, there is a down ward force on each electron of magnitude bev. Work purpose the hall effect is one of the most important effects in the determination of the parameters that characterize from the electrical point. Semiconductors what are semiconductors p type ntype semiconductors. Demonstration of the hall effect in semiconductors physlab.
This demonstration shows hall effect in semiconductor materials and shows how ntype and ptype semiconductors can be identified. Dec 10, 2004 this idea has led to much theoretical discussion 16, but experimental evidence of the spin hall effect has been lacking. Conductivity measurements in semiconductors cannot reveal whether one or both types of carriers are present, nor distinguish between them. The flow of electron is in the opposite direction to the conventional current. A stationary permanent magnet and semiconductor hall effect chip are mounted next to each. Hall effect is another important transport phenomenon and has been extensively studied in amorphous semiconductors. The hall effect describes the behavior of the free carriers in a semiconductor when applying an electric as well as a magnetic field. This idea has led to much theoretical discussion 16, but experimental evidence of the spin hall effect has been lacking.
The determination of the concentration of the charge carriers n or p. What is the hall voltage for intrinsic semiconductor. A semiconductor material has an electrical conductivity value falling between that of a conductor, such as metallic copper, and an insulator, such as glass. Its conducting properties may be altered in useful ways by introducing impurities doping into the crystal structure. The hall effect voltage, v h, and hall coefficient, r h, for the same sample will be measured using a magnetic field. We imagine that the charge carriers move in a medium that. The hall effect is the production of a voltage difference the hall voltage across an electrical. It is the development of a potential difference in a conductor transverse to the current passing through the. Ntype semiconductors have a large number of donors, dopant atoms that donate electrons to the conduction band. In this experiment, the hall effect will be used to study some of the physics of charge transport in metal and semiconductor samples. Although the hall effect sensor is a magnetic field sensor, it can be used as the principle component in many other types of sensing devices current, temperature, pressure, position, etc. In simple semiconductors with one kind of carriers dominating, t terpreta where e 1.
Observation of the spin hall effect in semiconductors science. Hall effect in electronics is explained with ntype semiconductor and ptype semiconductor in this video along with few applications of hall effect. Reif, fundamentals of statistical and thermal physics introduction in this experiment the resistivity and hall effect in a crystal of ntype. Hall observed that when an electrical current passes through a sample placed in a. Hall effect and resistivity measurements in doped gaas 1 experiment 14 hall effect and resistivity measurements in doped gaas note. The hall effect in polycrystalline and powdered semiconductors article in reports on progress in physics 4311. J x qn where j is the current density, n is the number of carriers and q is the charge defining the hall coefficient, r h 1qn, then e y v x. Scientific principles applications previous setup shortcomings new setup how it works possible improvements results conclusion hall effect. The hall effect describes the behavior of the free carriers in a semiconductor whenapplying an electric as well as a magnetic field. Published 2004 one day in the year of 1820, walking to his lecture at the university of copenhagen, oersted got an idea. So the hall voltage produced in the ntype semiconductor is negative. The determination of the hall mobility of the charge carriers in the respective semiconductor. The electrical conductivity measurements weve learnt so far are not sufficient for 1 the determination of number of charge carriers 2 mobility of the charge carriers 3 whether the conduction is due to electrons or holes hence, it was very difficult to differentiate between a p type semiconductor. The hall effect in polycrystalline and powdered semiconductors.
The hall coefficient is calculated based on experimental results and used to measure fundamental semiconductor properties of the given doped sample of. The hall effect also showed that in some substances especially ptype semiconductors, it is more appropriate to think of the current as positive holes moving rather than negative electrons. A current of 10 amps is flowing through the sample perpendicular to the magnetic field. A sample of copper of thickness 18 x 106 m is placed in a 0. The hall effect helps us to find the sign of the charge carried. In general, the method is used in conjunction with a conductivity measurement to also determine. Hall effect experiment department of physics and astronomy. Hall effect sensors can be applied in many types of sensing devices. In the ntype semiconductor, the electric field is primarily produced due to the negatively charged free electrons. The hall effect the hall effect describes the behavior of the free carriers in a semiconductor whenapplying an electric as well as a magnetic field. Hall effect, development of a transverse electric field in a solid material when it carries an electric current and is placed in a magnetic field that is perpendicular to the current. Hall effect and its applications in semiconductorsphysics. This causes the electron current to be deflected in a downward direction and causes a negative charge to accumulate on bottom face of slab. If static electricity did not affect magnets in any way, maybe things would be different if one tried electricity moving through the wire connecting the two poles of the volta pile.
For each semiconductor sample, you should do a hall scan for a relatively wider range of currents. The drude theory and the hall effect before considering the effect of magnetic fields on conductors, we need some model to describe the flow of currents in response to electric fields. Hall effect in semiconductors hall effect and mobility the hall effect is easier to measure in semiconductors than in metals, since the carrier concentration is smaller. One day in the year of 1820, walking to his lecture at the university of copenhagen, oersted got an idea. Ravindran, phy02e semiconductor physics, autum 20 17 december. She hall effect in semiconductor experimentation lab university. Mar 09, 2012 hall effect in electronics is explained with ntype semiconductor and ptype semiconductor in this video along with few applications of hall effect.
Semiconductor hall effect basic concepts, numerical on. The hall effect, which was discovered in 1879, determines the concentration and type negative or positive of charge carriers in metals, semiconductors. The importance of the hall effect becomes apparent when semiconductors are used, as we now see. The hall effect as presented by kishore padmaraju in experimental conjunction with greg smith alex pawlicki outline what is the hall effect. Being very simple and straight forward phenomena in physics, hall effect is a fundamental principle in magnetic field sensing and have many practical applications in our daily life. Hall effect experiment utk department of physics and. Theory as you are undoubtedly aware, a static magnetic field has no effect on charges unless they are in motion. Hall effect in semiconductors drift velocity for an electron in the xdirection is.