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E_g = 1.1eV, m_e = 0.26m_0, m_h =0.39m_0, my_e = 0.15m^2/Vs, my_h = 0.05m^2/Vs

I suppose m_e and m_h is the effeicient mass of the electrones and holes

my is the mobility and E_g is the bandgap

I got that the electron concentration is given by

N_e = N_c * exp((-E_g-E_f)/kT) where N_c = 2*(2*pi*m_e*kT/h^2)^(3/2)

N_h = N_v * exp(-E_f/kT) where N_v = 2*(2*pi*m_h*kT/h^2)^(3/2)

I can get E_f = E_g/2 + 3/4 * kT*ln(m_h/m_e) my formula sheet says that this is true for an intrinic semiconductor. In my ears that sounds like an n-doped semiconductor. How do I know if this semoconductor is n-doped? The assignment only says that it's doped with indium.

My other problem is that I just stumble in the dark here. Sure I find some fornulas that I can use, but what for? I dont really understand what the fermielevel is and even less how I calculate "What impurity density would cause the fermi level to coincide with the impurity level"

thanks in advance