Rate Equations for the Phonon Peak in Resonant-Tunneling Structures
Date of this Version11-15-1993
Phys Rev. B, Vol. 48, Number 20 (1993) 15132.
The ratio of the phonon peak current to the main peak current in double-barrier resonant-tunneling structures is significantly enhanced by barrier asymmetry. Previously, using the Keldysh formalism, we derived analytical expressions, valid in the zero-temperature, high-bias regime, which explained this eftect. We now provide analytical expressions valid for finite temperature and bias obtained from (i) an intuitive derivation using a rate equation approach and (ii) a more general derivation using the Keldysh formalism. The results of the two difFerent approaches are shown to be essentially identical for the ex- perimental device parameters. The finite temperature expressions shed light on the e8'ect of the Pauli ex- clusion factors in the contacts on the current. In particular, we show that in a transmission formulation, the transmission coefficients, T(c,c, ), are themselves functions of the Fermi factors in the contacts.
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