The figures of merit of different GALs as a function of the Fermi
energy are compared in Fig. 3.18. IsoTri has the highest
,
because it has the lowest lattice thermal conductance and one of the largest
Seebeck coefficients. At room temperature, the factor
has significant values only in the range of
around the Fermi level. Under the condition
, holes have no contribution to the total
electrical current. A large value of the Seebeck coefficient is therefore
obtained.
In our work we did not consider the passivation of dangling bonds at
the edges. However, it has been shown that hydrogen passivation of
dangling bonds results in further reduction of the thermal
conductance [70]. Therefore, a higher
for GALs can be
obtained by edge passivation.