Comments

Listed in Order of Receipt (with most recent at the top of the page)

• This is an extremely useful document for teaching, research and for industry.

• - Kuruppath Ravindran, CIARA, lordravindran@gmail.com

• How to measure transport properties (Hall mobility, carrier concentration etc.)of a 5 micron thick layer on a 500 micron substrate without separating it from the substrate (Separattion is technically not possible) ? Are the values obtained by van der pauw technique will be valid in this case?

• - Mahua Chakraborty, mb_energy20022002@yahoo.co.in

• why is the geometry of the sample used in the hall effect a rectangle????could you please give an detailed explaination.

• - akshay, iit delhi, aksy88@gmail.com

• well this is great , putting all the informations about hall effect on this site.i m working cobalt doped ZnO films and trying to look at anomalous hall effect in my smaples.i want to know that what all precution i have to take to do so as the samples are resistive(resistance is of the order od 100 kiloohms) and if anybody working on the same pls send some infomation on the below mentioned id. Thanks for cooperation.

• - manisha, IITDelhi, manisha_2017@yahoo.com

• Hi, I have finished doing my Hall effect system following all the instructions on this page, many thanks, but I need more information about the contact process, and need some samples already characterized to probe It. If someone can help me with something I'll be very thankfull

• - Luis Eduardo Vidal, Universidad Nacional de Colombia sede Manizales, luiseduardovidal@hotmail.com

• Hi! I'm searching for some old publications of Palatnik and Belova of 1966 and 1967 about the sistem Ag2Te-Ga2Te3, and I can't find them. Please, would you help me to find it out? Thanks!

• - María Elena Beltrán, LUZ, mbeltran_puricayahoo.com

• Thank you very much for the valuable information you`re providing in this website,for me it is perfect except for that part of algorithm solution since im not familiar with solution. If you generously allow me I`d like to ask a few questions: 1)While doing the Hall measurements,should the first four readings with the positive magnetic field be opposite in polarity to the next four readings with the negative magnetic field? 2)One kind of the samples im working on is amorphous sputtered Si thin film on a crystalline Si substrate,the (1cm*1cm) samples where annealead in the presence of an Al film over the amorphous Si film at different temperatures for different time durations. I want to know how can i do resistivity & Hall measurements,& I`ll be very grateful if you provide me with these information.thank you in advance.

• - Ma`in Bataineh, Institution: Jordan University of Science & Technology, mainbataineh@yahoo.com

• I am in the process of preparing a setup for Hall measurements. I am working on ITO films. I would appreciate if anybody doing Hall Measurements for ITO films would e-mail me back. Thanks Rajesh Chandra

• - Rajesh Chandra, rajesh_recw@yahoo.com

• Hi. Great Website!

• Recently I'm looking into the Hall measurement on my undoped samples. I had done the measurement before and after the post-annealing treatment. The as-grown samples are initially n-type conduction with mobility around 36 cm2/V-s, carrier concentration of 8.08E+18 cm-3, and resistivity of 0.022 Ohm-cm. However, after annealing, I found the interesting data. The resistivity increased by around 2 orders. More importantly, the mobility decreased to around 8 cm2/V-s or even lower. And the carrier concentration remained around the same (minor decreased but still in same order).

  Here are my doubts:

  (1) Why the hall mobility dropped for the annealed samples? From the XRD measurement, it is obvious that the crystallinity improved after annealing. From my point of view, since the annealing will annihilate the intrinsic defects (donors). Hence, the electron concentration decreased and became more comparable to the hole concentration after annealing. So, the measured hall mobility is the average of the carriers (electrons + holes) velocity. As a result, the hall mobility drop due to the combination of electron and hole conduction within the sample. Am I right to say this?

  (2) All the measurement were done at room temperature. From the resistivity measurement, we can speculate that the carriers of annealed film at RT are less compared to as-grown film. But from the measurement, it seems that it doesn't decreased much, for example, from 8.08E+18 to 1.56E+18 cm-3.

  I hope that you may clarify all the doubts i have. Thank you very much.

  Best Wishes,

  ST

• I am a researcher from a national laboratory, Taiwan . Recently, I have to purchase a Hall effect measurement system. From my survey, I know the Accent HL-5500PC and Lakeshore 7600 series fit our researches (transparent conductive oxide and doped nitride) and budget. Cloud someone who experienced using of those kinds of Hall system gives some suggestion for me? Thanks.

• Hi. I would like to know if I directly probe the 4 leads to my samples for the hall measurement, how will it affects the accuracy, especially on determining the conduction type.

  I was doing that because even without putting the ohmic contact by other metal, I still can obtained linear IV curve (nearly 45 degrees). Also, the samples will be heat treated after the measurement. Hence, making ohmic contact by metal is not feasible for my case.

  I'm extremely concerned with the conduction type of my films. So I sincerely hope that you may release my doubt.

  Thank you very much.

• I really appreciate this site for giving clear explanation and illustration on how to carry out the van der Pauws method. However, I have some question on how to choose the appropriate test current for a particular conductive material. I am particularly working on alumina and carbon composites that may have conductivity ranges from 10x-7 to 10x-3ohm-cm. Also, what should be the desirable thickness of the sample.  If possible, could you please send me an answer through the aforementioned email address. Thank you very much.

• I am the sales manager for Abbess Instruments in Holliston , MA .  Our web address is www.abbess.com. We are in the process of developing a low cost Hall Effect Measurement System that we hope will sell for around $20k. I found your site to be extememly helpful and I will almost certainly contact you for round robbin test samples, etc. I will be putting together a survey/market analysis form to get inputs as to the measurement range requirements and desired accessories for a practical, moderately priced system. Anyone wishing to give me inputs on our proposed system is encouraged to contact me at my email address. Thank you.

• Hi, everyone,

• Charles PanIn a commercial system for Hall Measurement, which also using the van der Pauw technique, AC current was also used in addition to DC current. what's the different between DC and AC current?

• hi, great site! my thesis is on nanostructured Si, and part of it is performing Hall effect measurements. i wanted to try to do an arrhenius-type measurement (ie concentration Vs Temperature) above room temp.
  do u guys perform these measurements, if so what apparatus do u use to heat the sample, and where can i find more info on sample heaters?
  thanks, ed

• I am measuring sheet resistance and hall voltage as suggested by your method for amorphous silicon. We are facing some problem with measuring hall voltage precisely. How to neglect the offset and other voltages? As shown in your data sheet, we have calculated hall voltages accordingly. Its not giving good results. Could you please write me, how to mainly eliminate the offset from hall voltage? Thanks.

• Because is not recommended to do the contacts at the edges or inside the perimeter for Sample geometries square or rectangle?

• hello, I wish to have some informations concerning the realization of ohmic contacts on semiconductor the familiy I-III-VI2 for the need of a caracterisation by Hall effect, and if it`s possible to use Indium (In) and at which temperature. And that type of flow is the advisable more to do the contacts on this type of semiconductors? Thanks.

• hello, I wish to have some informations concerning the realization of ohmic contacts on silicon substrate doped p+(with boron) for the need of a caracterisation by Hall effect, and if it`s possible to use Indium (In) and at which temperature. Thanks.

• I would like to learn more about the effect of varying the magnetic field strength, and the effect of temperature on parameters measured during Hall Effect measurements.

• Very fine. But it is better to have calculation programs on Mathimatica. Thank you.

• Why do you use complicated algorythm to solve this equation instead of using formula proposed by van der Pauw Rs=pi*d/ln(2)*(RABCD+RBCDA)/2*f(RABCD/RBCDA) ..... f - simple function

• Very nice, clear description of Hall-effect material characterization. We could learn much more from your job. It's an excellent website.

• This is very good work, But i would like to ask, why you use resistance in the equation of van der Pauw for calculation insted of Resistivity. Second, i would like to have reference no. 3 and 4, please if you can copy and send it to me it will help me much. again thank you for your nice work.

• Nice work. I have a question, answer to which i could not find here. What are the additional precautions one must make while working with ultra thin films?? also does the set up remain the same for highly doped and lowly doped films??

• I was interested in knowing the effect's of the "Hall effect" on the working of the transistor. I would be really obliged if i can get a answer through an email or through a posting. Thank You.

• Hello, I recently perfomed an experiment that involved the Hall Effect. I have on question that has me confused. Can the Hall Effect be used to determine what type of doping (n- or p- type) of a sample? I would love to hear some opinions on this matter.

• Excellent website! We could learn much more from your job. I would like to ask a question: How to fabricated the ohmic contact if I want to obtain the mobility of SiC epilayer grown on Si substrates, while the Si substrate is p or n-typy conducting? How to determine if the contact is ohmic? Thanks very much for your kind interpreting.

• I am currently working on overhauling an old "homebuilt" hall effect measurement setup here, and I would like to know what the preferred method is for attaching wires to the hall effect sample, or if some mechanical means of making electrical connections to the ohmic contacts (e.g. using spring-loaded pins) would be preferable. Thanks!

• I would like to do Hall measurement on high temperature superconductors to see the sign reversal of the Hall voltage. How can i do this?

• Why can we caculate Vh as all Vs measured within applied B field summed or subtracted? What does that Vh mean? Please mail me the answer or the website which contains the answer. I can't find it on this site. Thanks a lot!

• Is it possible to measure the Ionic Hall effect in Rubidium Silver Iodide (or in Silver iodide) in compact pressed pallet form by using alternating current and alternating magnetic field method?

• Could you tell what kind of technique did you use for making vdP shapes or Hall bars? What would you reckon about the error coming from it?

• Just wonder how did you deal with Hall factor in your measurements? Or say, what magnetic field did you use? What do you think about errors coming
  from multi-carrier transport and non-degenerate carriers? Anyway, I've puzzled by these for a while.

• Very nice, clear description of Hall-effect material characterization. I recommend adding two citations to your references:
  • Solid-State Electronics, Vol. 20, pp. 681-687 (1977). Four-Point Sheet Resistance Correction Factors for Thin Rectangular Samples, David S. Perloff
  • Solid-State Electronics, Vol. 22, pp. 645-650 (1979). Surface and Interface Depletion Corrections to Free Carrier-Density Determinations by Hall Measurements, A. Chandra, C. E. C. Wood, D. W. Woodard and L. F. Eastman

• What are the error likely to occur if we use a geometry as shown on fig. 4c compare to the geometry in 4a or 4b? NB: i am working on thin film.

• I think this site is very instructive, and it's cool. I have a question, though. The preferred sample sahpe for the resistivity measurment seems rather difficult to achieve/prepare, though. How can I get a sample shape like yours? How did you get that shape?

• I would like to have a copy of Ref.2,3,4,8,9,10.Is it possible?

• Are you experienced in measurement of the Hall effect in a two layer samples (when the applied current diffuses in the second layer), for example when whe want to measure the parameters of a semiconducting layer on a conducting substrate of the same type of conductivity? How we can calculate the resistivity and the Hall factor of the upper layer if we know the parameters of the second layer (the substrate). Have you got any solvers of the Laplaces ecuation for solving this problem?

• It is very useful and somewhat detailed description on Hall effect measurements. Please send me details about the apparatus used (electromagnet & its accessories, measuring systems plus relevant electrical circuits, cryogenics and other accessories, software as well as their manufacturing companies.

  We are going to be involved in Hall effect and resistivity measurements on low- and high-impedance samples.

  I'll really appreciate your kind help and fruitful cooperation, with many thanks in anticipation.

  - Mousa M. Jafar, Department of Physics, University of Jordan, mmmjafar@yahoo.com
• Informations about the hall measurements and electrical conductivity measurements are ideal for research and teaching. It is very difficult to get all these informations at one place. I use your description for my teaching at M.Sc. level as well for my research work. My students have used your informations and found it very educative. I congratulate you for putting detailed informations about this techniique so elegantly and clearly that my students find it very useful.

  Thanking you for such greast work

• Excellent description, I found it very useful. What are the units for the symbols used in this document? Is there a nomenclature section somewhere?

• Bravo! site superbe et documentation de premier choix. Merci! (Translation: Bravo! Superb site and top-quality documentation. Thank you!)

• Is it possible? If I would like to obtain copies of the reference number 4,5,8-10. Thanks, F. Manu

• Oi, gostaria de saber se a corrente I21 significa que é uma corrente de elétrons que sai 2 e vai para o pino 1 , ou se é o contrario ? Até.

• Oi também tenho duvidas de como calcular o Rs usando aqueles procedimento, oque siginifica I elevado a th ? Afinal como se calcula O Rs ? Gostaria que alguem me fizesse um exemplo usando aquele algoritmo sugerido na seção IV . Até,

• Oi, estou querendo reproduzir o efeito hall, gostaria de saber mais detalhes técnicos do experimento.

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Date created: 6/30/2005
Last updated: 1/30/2008