Thermal properties of chalcopyrite semiconductors

Abstract

Thermal properties (i.e. lattice thermal expansion coefficient, α_L, and heat of formation, −ΔH _f) of chalcopyrite-structured solids were evaluated. Values of α_L of and chalcopyrite semiconductors exhibit a linear relationship when plotted on a log–log scale against the nearest neighbour distance, d (Å), 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^IB^IIIC₂ ^VI and A^IIB^IVC₂ ^V chalcopyrite semiconductors provides a better agreement with experimental data as compared to the values evaluated by earlier researchers. The results for α_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.

Keywords:

• lattice thermal expansion coefficient
• heat of formation
• chalcopyrite semiconductors