Thermal properties of chalcopyrite semiconductors

Thermal properties (i.e. lattice thermal expansion coefficient, alpha L, and heat of formation, -Delta H-f) of chalcopyrite-structured solids were evaluated. Values of alpha L of A(I)B(III)C(2)(VI) and A(II)B(IV)C(2)(V) chalcopyrite semiconductors exhibit a linear relationship when plotted on a log-log scale against the nearest neighbour distance, d(angstrom), but fall on two straight lines according to the ionic charge product of the compounds. On the basis of this result, a simple lattice thermal expansion-heat of formation relationship is proposed and used to estimate the heat of formation of these semiconductors. Application of the proposed relationship to A(I)B(III)C(2)(VI) and A(II)B(IV)C(2)(V) chalcopyrite semiconductors provides a better agreement with experimental data as compared to the values evaluated by earlier researchers. The results for alpha L differ from experimental data by 4% for ZnSiP2, 4.6% for ZnSnP2, 3.7% for CdGeP2, 0.78% for CuGaS2, 1.7% for CuGaTe2 and 4.3% for AgGaSe2. The results for heat of formation differ from experimental data by 2.9 for ZnSiP2, 0.9% for ZnGeP2, 0.97% for ZnSnP2, 1.9% for ZnSiAs2, 3% for ZnGeAs2, 4.8% for ZnSnAs2, 3.4% for CdGeP2, 2.7% for CdSnP2, 0.49% for CdGeAs2, 1.6% for CdSnAs2 and 3.8% for CuGaSe2.