Do you mean experimental technique by 'model'? Photoluminescence (PL) is an experimental technique, not a model.

Positrons, conductivity measurements as a function of temperature, bulk thermal expansion compared to lattice parameter measurements over an extended temperature range by x-rays or neutron diffraction

@ kanad Mallik

Sir,

Thank you for correcting my question . I need a technique for estimation of concentrations of defects in semiconductors

Use radiative tracer of silicon to determining the vacancy concetration.

Refer to old Shewman's book 'Diffusion in Solids" or other related.

You have to keep thermal equilibrium condition for the spices befor during measurement.

You can determine type (for electron or hole), capture cross section and concent of defect using deep level transient spectroscopy,DLTS, (D.V. Lang J. Appl. Phys. 45, 3023 (1974)) or photo -induced transient spectroscopy, PITS (A.Erol Semicond. Sci. Technol. 18 (2003) 968–972) In the DLTS techniques, you make schoctky contact or p-n junction, but in the PITS, you need only two contact on the sample.

I'm also agree with Mr. Donmez to use DLTS if you can make a good schottky barrier on your sample. On the other hand, I strongly suggest to use Hall effect measurement to find them.

If you are working with PL, you might find thermally stimulated luminescence (TSL) very useful for detection of defects and luminescence centers. Have a look at these references about TSL:

http://link.springer.com/article/10.1007%2FBF02897907?LI=true

http://arxiv.org/ftp/arxiv/papers/0704/0704.0568.pdf

You can also search for very recent articles on this topic.

@Lakshmi Prasanna

A number of good techniques have been suggested. Each of them have their strengths and problems. Important aspects are: your sample material, which particular defect, and the minimum concentration of the defect you like to investigate. The total length of your research project is also very important as for each of these techniques, you will need time to get validated results for your samples.

From your other posts, it seems that you have the facility to use temeprature-dependent PL and you like to look at vacancies in ZnO, particularly the vacancy-free carrier correlation. Can you do the PL decay experiment? Another good suggestion made by Kasra Behzad is Hall effect measurement. That needs to be temperature-dependent. DLTS is a very relevant experiment, but you will have to overcome too many contact-related issues. In general, this point is valid for all the electrical techniques suggested as ZnO is a high bandgap material, and so is likely to be highly resistive electrically. Only the Hall experiment here can use four terminal measurements to avoid the problem.

if you can give more details of your samples, you may get more useful suggestions from this forum.

Undoped semiconductor materials include various structural defects such as the intrinsic defects and the residual impurities. Doping of semiconductors allows both to introduce new impurity defects and to modify their intrinsic defects. In this case the intrinsic defect concentration is changed. At the same time it is possible the formation of complex defects with the participation of the intrinsic defects (for example, cation vacancies) and the impurity atoms. Thus, the distribution of the intrinsic and extrinsic defects may be very complex and that depends on the impurity concentration. Therefore, in this case it is possible really to determine only the relative concentrations of various defects. PL measurements are effective method to study the defect structure of semiconductor materials. However,as noted in previous comments it is very useful also use other techniques. Usually, we use both the photoluminescence and photodiffusion current measurements to study the defect structure of doped semiconductor materials.

You can use temperature dependent DLTS measurement to predict the concentration and trap level of the defects

DLTS method is very important to investigate the deep levels. However, the energy levels caused by the vacancies are usually shallow.

I agree with Yuri Gnatenko.

My original answer is appropriate for understanding the intrinsic defects,vacancies, divacancies, multivacancies and other lattice defects in a highly purified element or compound. It relies on a multifrequency Einstein empirical model of both the lattice vibration distribution obtained from least square fits to expansivity or thermal expansion data from near absolute zero to approximately 2x the Debye temperature(see our papers on Al in Phil Mag and later ones on refractory metals. Also important at higher temperatures are theoretical models of single and multivacancies as a function of temperature. One of these was published in Physical Review in the 1960-70 timeframe by Marshall Kreitmann et al. I defer to previous responders for their answers for electronic device defects determination. Various Positron, types of spectroscopic and electrical techniques have all been used with varied success by many investigators.

I'm also agree with Mr. Donmez