Short answer: Hall measurement.

Short answer: Hall measurement.

Dear Muhammad,

I quote a part of a clear explanation answering a similar question:

You need to use the Hall effect. If you have an electric current flowing in x direction and apply a magnetic field in y direction, the charge carriers will see a Lorentz force in z direction. This is sensitive to the sign of the charge carriers (electrons or holes). The force will move the charge carriers to the edge of the sample. This inhomogeneous distribution creates an electric field opposing the Lorentz force. You can measure this voltage, its sign shows which charge carriers are in majority. With the formulae of the Hall effect you can even calculate the charge carrier density.

Source: http://goo.gl/dKM0xc

A quick method is 'hot prob' method. For confirmation use Hall effect as Behnam and Mohammed said.

Another long rout in case you have no access to Hall is:

(i) Make an MOS capacitor on this semiconductor

(ii) Measure capacitance- voltage for different voltages (C-V curve)

(iii) Draw 1/C^2 vs voltage.

(iv) If the linear portion of the graph has positive slope then it is a p-type semiconductor;other wise n-type.

Regards

Rajeev.

Another method is Seebeck coefficient measurement. N-type semiconductors have minus Seebeck and p-types have positive Seebeck.

Hot probe point test is the quick way to determine whether the semiconductor is n- type or p-type.

Hot point probe is a method of determining a semiconductor sample is n type or p type. A voltmeter or ammeter is attached to the sample, and a heat source, such as a soldering iron, is placed on one of the leads. The heat source will cause charge carriers to move away from the lead. This will cause a current/voltage difference.

if the heat source is placed on the positive lead of a voltmeter attached to an n-type semiconductor, a positive voltage reading will result as the area around the heat source/positive lead becomes positively charged.

You may try Mott-Schottky plots too in an electrochemical setup. This would give you you the flat band and the carrier density too.

There are 2 or 3 methods to find if a semiconductor is p- or n-type:

1) Hall measurement

2) Seebeck Coefficient Measurement etc. but the easiest is

3) Hot Probe measurement; in this you can the two probes of a multimeter (voltmeter) along the length of the semiconductor and heat one end of the material. Now depending on the direction of the current flow an emf will be generated either negative direction or positive direction.

Hot probe measurement is a good idea but it requires long semiconductor and cooling another end of it. Not easy but possible

I agree with the others on what the differences are. An additional difference lies in the relationship to the fermi level. I believe for a p-type, the fermi level is at the top of the conduction band, and for an n-type, it is at the bottom of the valence band. For insulators, it is right on the middle, and metals have no band gap.

I am very grateful to all of you for such informative answers!

Thank you!

Dear Kyle Robinson,

For p-type semiconductor the Fermi level is just above the valance band and for n-type it is just below the conduction band.

Regards,

Rajeev.

Hall measurment and Hot probe technique both are good and easiest method to check the semiconductor.

Hall effect is an effect that is generally used to identify the type of semiconductor. When the Hall sensor is placed in a zone with a magnetic field and it is crossed by an electric current that is perpendicular to the field, a voltage difference (Hall voltage) appears in a direction orthogonal both to the magnetic field and the electric current, with a value that is proportional to the product of the magnetic field and the electric current amplitudes. The Hall voltage is an indicator of the semiconductor type doping (donor or acceptor), in the sense that it presents different signals for n-type semiconductors and p-type semiconductors. In effect, the magnetic force has the same direction, independently of the type of majority carriers in the semiconductor. In p-type materials the charge that moves is positive; in n-type materials the mobile charge are electrons. This leads to voltages with opposite polarities in the two mentioned situations. In order to have a high sensitivity measurement, the magnetic field shall be positioned in the direction of the smallest dimension of the Hall sensor.

Hot probe is one of the ways that you can determine if your sample is ntype or ptype.

In this method you provide a thermal current and then you measure the polarity of produced voltage. You can arrange the experiment even by a soldering iron ( depend on your sample).

If you have any question about the process just ask.

In the p-type semiconductor the essential charge carriers are holes (positive) and in the n-type semiconductor the essential charge carriers are electrons (negative). A specific method to define if the charge carriers are positive or negative is the Hall - effect. According to sign of the Hall tension in the sides of the conductor with electric current set in the magnetic field, you can determine if the essential charge carriers are positive or negative.

An intrinsic semiconductor has no deffect on the crystalyne structure, the semiconductor characters comes from the small distance between the conduction and valency bands. If you dope the semiconductor with trivalent ions, such as B, then a permited energy level is creaed insde the forbiden band, an electron can easily jump to this level, creating a hole inside the valency band.Then the conduction is due to the holes in the valency band, that behaves as positive charges: you have a p-type semiconductor. If on the contrary you dope the semiconductor with P, it provides an extra energy level with an electron near the conduction band. This electron jumps to the conduction band and hence, the conduction is due to electrones. I agree that the most easy way to confirm the type of semiconductor is by performing a Hall effect experiment.

[Are you a student at C.A.S.?] A semiconductor has both positive charge carriers and negative carriers. P-type semiconductor has more positive carriers than negative carriers (hence p-type), and N-type is the opposite. This applet may help:

http://jas.eng.buffalo.edu/education/semicon/fermi/bandAndLevel/fermi.html

The hot probe technique is probably the simplest technique to determine the type. The (majority) carriers will flow from the hot spot toward the cold spot, hence the hot spot will show positive voltage in p-type and negative voltage in n-type.

Semiconductors are the substances which conduct more current than insulators. When an element from Group IV is doped with Group V elements, then an extra electron (4+5=9) is available for conduction and therefore such semiconductor is called n-type semiconductor means negative as electron carries negative charge. When the same group is doped with Group III elements, the resulting semiconductor is called p-type semiconductor means positive as there is a deficiency of electron (4+3=7) and in general term called positive hole.

Let us take the specific example of CZ grown GaAs for instance. Would the presence of excess stacking faults due to missing Ga rows or As rows change the "p-type" or "n-type" characteristic of the material locally?

Electrical Properties of Dislocations in Semiconductors, R. Labusch and W. Schroter. From Dislocations in Solids, Editor F. R. N. Nabarro, Volume 5, 1980.

pp. 162.

"8. Dislocations in III-V compounds

In III-V compounds the two face centered sublattices of the diamond structure are occupied by different kinds of atoms. The (111) slip planes are alternately occupied by atoms of group III and atoms of group V. The core of an edge type dislocation therefore may consist of atoms of group III or group V, depending on the sign of the dislocation. As first pointed out by Hansen [87], the dynamical and electrical properties of the two types should be different on account of their different cores.

This qualitative statement is fully confirmed by velocity measurements of single dislocation half loops in InSb [39, 88-90] and GaAs [90]. So far, the electrical properties of dislocations have been studied in detail only for InSb [6, 91-97].................."

pp. 183.

"Core configuration of dislocations in semiconductors:

The diamond structure has a cubic face-centered space lattice with a basis of two atoms. The stacking of {111}-planes in Si, Ge and many III-V compounds is that of the face-centered cubic structure, except that in the diamond structure each layer consists of two atomic planes. The spacings between adjacent {111}-planes are alternately narrow and wide in the ratio 1:3. Consequently there are two sets of glide planes and two sets of dislocations. If the glide occurs between two widely spaced planes, the dislocations belong to the shuffle set, if between two narrowly spaced planes, it belongs to the glide set. Complete dislocations in the shuffle set are believed to be stable, while those of the glide set are unstable with respect to a dissociation into two Shockley partials with a stacking fault between them; the reaction is of the usual type:

1/2a[110]----->1/6a[211] + 1/6a[121]............................"

the only difference is the carrier type. In p-type semiconductor the electrical carrier is hole and in the other the electrical carrier is electron. There are many method to check the type, say, thermal probe method, Hall effect measurement

The concentration of charge carriers – conductivity – of intrinsic semiconductors is often increased by their “doping”, introduction of foreign, hetero-atoms of a different element. If the impurity atoms have more electrons than the atoms they replace, the extra valence electrons will be “donated” to the conduction band, and the negatively charged electrons will be the majority charge carriers, resulting in an n-type semiconductor. Conversely, if the impurity atoms have fewer electrons then the intrinsic atoms they replace, positively charged holes, which can accept electrons from the conduction bands will be formed, and be the majority charge carriers in the resulting p-type semiconductor. Doped, extrinsic semiconductors are important in transistors, diodes, and similar semiconductor devices.

P-type or N-type implies the major conducting carriers in a semiconductor. In p-type one, the major conducting carriers are electrons, meanwhile, these are "holes".

The convenient method for determine the type of semiconductor is using Hall measurement.

N-type semiconductor has negative electron charge carriers, whereas, p-type semiconductors have positive holes as charge carriers.

Hot probe is one of the ways that you can determine if your sample is ntype or ptype semiconductor. But however, one can also perform the Hall effect experiment to determine if the semicontor is a ptype or an Ntype material.

And again, An intrinsic semiconductor has no deffect on the crystalyne structure, the semiconductor characters comes from the small micro distance between the conduction band and valency bands. If one dopeed with trivalent ions, such as Boron, then a permited energy level is creaed insde the forbiden band, an electron can easily jump to this level, creating a hole inside the valency band and as such the conduction is due to the holes in the valency band, that behaves as positive charges: you have a p-type semiconductor. If on the contrary you dope the semiconductor with P, it provides an extra energy level with an electron near the conduction band. This electron jumps to the conduction band and hence, the conduction is due to electrones.

Thermoelectric power measurements is the best technique as Hall effect sometimes show opposite sign particularly in amorphous semiconductors.

I agree with the above replies; Hall Effect Measurements is the best to know the conductivity of a semiconductor.

Probably not the best (the Hall measurement is the best one), but just to add some variety to the answers you can use Raman spectroscopy to do that. For instance, in Silicon, the Fano effect will make the Raman peak asymmetric to low or high frequencies depending on the doping type.