High-temperature sensitivity complex dielectric/electric modulus, loss tangent, and AC conductivity in Au/(S:DLC)/p-Si (MIS) structures
A. Tataroğlu, Hülya Durmuş, A. Feizollahi Vahid, Barış Avar, Ş. Altındal
Abstract
Abstract Complex dielectric ( ε * = ε′ − jε″ )/electric modulus ( M * = M′ + jM ″), loss tangent (tan δ ), and ac conductivity ( σ ac ) properties of Au/(S-DLC)/p-Si structures were investigated by utilizing admittance/impedance measurements between 80 and 440 K at 0.1 and 0.5 MHz. Sulfur-doped diamond-like carbon (S:DLC) was used an interlayer at Au/p-Si interface utilizing electrodeposition method. The capacitance/conductance (C/G) or ( ε ' ~ C) and ( ε ″ ~ G) values found to be highly dependent on both frequency and temperature. The increase of them with temperatures was attributed to the thermal-activated electronic charges localized at interface states ( N ss ) and decrease in bandgap energy of semiconductor. The observed high ε ′ and ε ″ values at 0.1 MHz is the result of the space/dipole polarization and N ss . Because the charges are at low frequencies, dipoles have sufficient time to rotation yourself in the direction of electric field and N ss can easily follow the ac signal. Arrhenius plot (ln( σ ac ) vs 1/ T ) shows two distinctive linear parts and activation energy ( E a ) value was found as 5.78 and 189.41 from the slope; this plot at 0.5 MHz is corresponding to low temperature (80–230 K) and high temperature (260–440 K), respectively. The observed higher E a and ε ′ (~ 14 even at 100 kHz) show that hopping of electronic charges from traps to others is predominant charge transport mechanism and the prepared Au/(S:DLC)/p-Si structure can be used to store more energy.