Measurement of the specific heat and determination of the thermodynamic functions of relaxed amorphous silicon

The specific heat, c_p, of two amorphous silicon (a-Si) samples has been measured by differential scanning calorimetry in the 100-900 K temperature range. When the hydrogen content is reduced by thermal annealing, c_p approaches the value of crystalline Si (c-Si). Within experimental accuracy, we conclude that c_p of relaxed pure a-Si coincides with that of c-Si. This result is used to determine the enthalpy, entropy, and Gibbs free energy of defect-free relaxed a-Si. Finally, the contribution of structural defects on these quantities is calculated and the melting point of several states of a-Si is predicted.