Thermoelectric properties of finite two-dimensional quantum dot arrays with band-like electronic states

The thermal power (PF = S²G_e) depends on the Seebeck coefficient (S) and electron conductance (G_e). The enhancement of G_e will unavoidably suppress S because they are closely related. As a consequence, the optimization of PF is extremely difficult. Here, we theoretically investigated the thermoelectric properties of two-dimensional quantum dot (QD) arrays with carriers injected from electrodes. The Lorenz number of 2D QD arrays in the resonant tunneling procedure satisfies the Wiedemann-Franz law, which confirms the formation of minibands. When the miniband center is far away from the Fermi level of the electrodes, the electron transport is in the thermionic-assisted tunneling procedure (TATP). In this regime, G_e in band-like situation and S in atom-like situation can happen simultaneously. We have demonstrated that the enhancement of G_e with an increasing number of electronic states will not suppress S in the TATP.