The mobility = e*relaxation time/eff.mass

(if this can help you)

Effective mass is the mass of election while it's velocity is relative to speed of light 

larger effective mass represents a smaller velocity and vice versa

this explains higher effective mass for electrons facing larger scatering numbers of course a smaller effective mass for a less scattering points, scatering points could be defects, impurities, boundaries, ----

Thanks for the explanation.

But I have got opposite result that of you suggested.

For higher effective mass I got lesser scattering (higher relaxation time).

Isn't it contradicting??

The relaxation time is controlled by the inelastic collisions, which means that the large linear momentum associated the heavy effective mass for a given kinetics energy (E=h2k2/2me)  requires much greater numbers of collisions to transfer its  kinetic energy to the targeted   point and even line defects in the bulk matrix. That means heavy electron has to travel much longer distance due to multiple collision, which is also determined by the concentration of  the defect centers inversely.  In the case of electron -phonon interactions problem might be more complicated, but follows up the similar trend. Where h  is h-bar. 

Dear Dr. Arindam Mallick 

Have a nice day and good times

The appended paper may help you, where there are many opto-electrical parameters concerns your study have been determined.

Good luck

https://www.researchgate.net/publication/294426798_Studies_on_dielectric_properties_opto-electrical_parameters_and_electronic_polarizability_of_thermally_evaporated_amorphous_Cd50S50-xSex_thin_films

Article Studies on dielectric properties, opto-electrical parameters...

The mobility = e*relaxation time/eff.mass

(if this can help you)

In deformation-potential acoustic phonon -electron scattering the relaxation time is proportional to (density-of-states effective mass)^-1.5. if the carrie.r distribution is fixed

Dear Jan,

Would you mind explaining a little bit.. in a easier way...

Thanks 

Dear Vesselin Donchev:

I have found effective mass using that equation only. I would like to know some physical details... the significance of m* during carrier transport through semi conductor.

Calculated relaxation time using conductivity, and plasmon energy.

@ Ahmed Saeed Hassanien:

Thank you Sir, for the upload.

According to Einstein and Nerst  the definition of mobility of a particle moving in a viscous media without acceleration any is  velocity/force.  By simple dimensional analysis it shows that ''as Vesselin claimed'',    mobility  mhu= F/V, which   has the dimension of  [time/mass], which means  his equation is correct with a missing steric factor. 

SEE: Kittel Page 230-231;   Mhu= e THo/Mass  (in Electrostatic FİELD)