Nd dopant effect on structural properties of BiFeO3 thin films and application in a negative capacitance transistor

When Nd doping in BiNdFeO (BNFO) film exceeds 10%, the two diffraction peaks (104)/(110) merge into one sharp single peak with increasing addition of Nd. It seems that a phase structural distortion can be obtained due to the substitution of Nd3+ ion for Bi3+ ion. For ferroelectric properties, among all Nd-doped (0%–20%) BiFeO3 capacitors, the BNFO capacitor with 10% Nd doping shows a higher Pr value due to a phase structural distortion and a lower leakage current. In a resistive-capacitive circuit diagram, the transient response of the voltage (V FE) across the BNFO capacitor can be measured. We demonstrate that the capacitance value d Q t d V FE t is negative in the spike interval of V FE(t), with the result that the negative capacitance of BNFO with a 10% Nd doping capacitor can obviously improve the I DS–V GS characteristics of a control thin-film transistor.