Quite often, transverse and longitudinal effective mass of electrons in Si and Ge are mentioned. Is there a way to find if a certain semiconductor has such directional nature for effective mass or not from band structure? Does parabolic band approximation mean that electron has isotropic effective mass (i.e equal longitudinal and transverse effective mass)? If someone could provide me with a reference or two, I would be really grateful.
Thanks in advance.
This reference will surely help you.
regards
https://www.amazon.com/Solid-Semiconductor-Physics-Philip-McKelvey/dp/0898743966
Ragib: For parabolic band approximation, evidence suggests that effective mass is isotropic and 3-D density functional theory can be applied to determine this isotropic effective mass from mxx, myy and mzz information. Otherwise for anisotropy, effective mass tensors for different crystallographic directions need to be found out from tensor matrices. For anisotropy, conduction band minima and valence band maxima vicinity in the E-k diagram turns out to be non-parabolic. In fact even for isotropic effective mass you may not get parabolic E-K profile if the valence band maxima and conduction band minima exhibits certain degree of non-parabolicity that depends on field and doping and crystal lattice structure.
I am attaching few papers for your reference. Hoping they will be useful. Please recommend my answer if it is useful for your query.
Sincerely,
Dr. Nabil Shovon Ashraf.
Ragib:
I am attaching two more lecture notes paper, one being from MIT lecture classes should give you enough information to determine your effective mass for both isotropic and anisotropic cases using the accurate information shared in these notes.
Sincerely,
Dr. Nabil Shovon Ashraf.
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