Usually, the procedure for identifying wurtzite and zinc blende are by doing diffraction in the TEM, observing that both Diffraction Patterns are present (WZ and ZB) and by doing dark filed on the diffraction spots of each phase. If the relative orientation is appropriate, you can get an image of parts of the sample in each phase. The spatial resolution will not be as high as in your image, but a clear and sound identification is possible. I would really recommend this procedure if it can be applied in your case. If you really need to know the phase of very small structures, then I would suggest Convergent Beam Diffraction. It is a technique that is not very often used, but that is very powerful. In this case, however, you would not get an Image but could perform a series of CBD on each feature of interest. 

We have carried out such HRTEM analysis of BN. You would need a smaller pixel size (higher magnification or more pixels), also the coherence of the illumination needs to be improved (smaller condensor aperture or larger illumination field). The evaluation is done first of all via the FFT. Later you should do contrast simulations via JEMS or MacTempas.

http://journals.aps.org/prb/pdf/10.1103/PhysRevB.46.10086

http://cimewww.epfl.ch/people/stadelmann/jemsWebSite/jems.html

http://www.totalresolution.com/

Article Microstructure study on BN nanocomposites using XRD and HRTEM

Article Synthesis, microstructure and hardness of bulk ultrahard BN ...

@Luiz, thanks for your comments. Let me attach a highly-cited paper where ZB and W phases are identified using TEM images.  Could you tell me how they did identify such phases without doing the XRD? Thanks again.

Dear Arafin,

It is necessary  to take the correct diffraction patterns of mentioned structures (ZB or W). After taking the correct diffraction pattern it is possible to calculate and proof your structures after several calculations.

Best,

Emre

Hope you are also familiar with our published work on SP (sphalerite) and W using XRD technique.

@Sarveswara, Could you please share the link of your published work? Thanks

K. Sarveswara Rao, R.P. Das, P.G. Mukunda and H.S. Ray. Use of XRD technique in a study of ammonia leaching of multimetal sulphides, Metallurgical Transactions B, Vol. 24B, December 1993, pp. 937-945.

K. Sarveswara Rao, The role of solids characterization techniques in the evaluation of ammonia leaching behaviour of complex sulphides, Mineral Processing and Extractive Metallurgy Review, 2000, Vol. 20, No.1, pp. 409-445.

I can be reached at: http://katragaddasarveswararao.com

You can identifiy ZB an W directly in HRTEM images. But you need to know the zone axis (za) first. It looks for me like a -za of ZB, but with uncertainty because of the small resolution of the uploaded picture. To be sure you need the FT of the HRTEM image. You should find a nearly six-fold symmetry with one elongated direction in the FT, this would be the pattern.

In the HRTEM just look for the periodic sequence "ABC" or "AB" along the closed-packed layers from the left to the right. If it is a -za - and for me it looks like one - your have ZB structure of GaAs. I can only identify a ABC-sequence of the close-packes layers. Maybe there are some hexagonal stacking faults, but the major sequence is ABC and hence ZB structure.