通过修正的Landau-Devonshire热力学模型构建了PbZr0.4Ti0.6O3/SrTiO3异质结的电滞回线方程, 得到了剩余极化强度Pr、矫顽电场Ec和有效储能密度Wrec的关于PbZr0.4Ti0.6O3薄膜厚度h的解析函数, 进而研究了连续厚度h对PbZr0.4Ti0.6O3薄膜铁电性能和铁电储能性能的影响。结果表明, Pr, Ec 和Wrec均随PbZr0.4Ti0.6O3薄膜厚度h的增加呈非线性增大, 且当厚度h分别为57.0 nm、64.2 nm和65.8 nm时, 达到饱和值75.3 μC·cm-2、2 240.7 kV·cm-1和9.0 J·cm-3, 而能量转换效率η随h的增加呈现出非线性减小, h接近52.6 nm时, η趋于一稳定值4.79%。此外, 瞬时相对变化率W′rec(h)和η′(h)均随h增加而减小, 当h小于2.4 nm时, η′(h)大于W′rec(h), 当h大于2.4 nm时, η′(h)小于W′rec(h), 且当h接近50.0 nm时, η′(h)/W′rec(h)趋于一稳定值0.65。

The hysteresis loop equation of PbZr0.4Ti0.6O3/SrTiO3 hetero-junction was constructed by the modified Landau-Devonshire thermody-namic model, and the analytical functions of remanent polarization intensity Pr, coercive electric field Ec and effective energy storage density Wrecwith respect to the thin film thickness h of PbZr0.4Ti0.6O3 were obtained, respectively, and then the effects of the thickness of the PbZr0.4Ti0.6O3 thin films on ferroelectric properties and ferroelectric energy storage properties were investigated. The results show that Pr, Ec and Wrec all increase nonlinearly with the increase of PbZr0.4Ti0.6O3 film thickness h, and reach saturation values of 75.3 μC·cm-2, 2 240.7 kV·cm-1 and 9.0 J·cm-3 when the thickness h is 57.0 nm, 64.2 nm and 65.8 nm, respectively, the energy storage conversion efficiency η, however, decreases nonlinearly with the increase of h, reaching a stable value of 4.79% when h is close to 52.6 nm. In addition, both W′rec(h) and η′(h), the instantaneous relative rates of change, decrease with the increase of h, when h is less than 2.4 nm, η′(h) is greater than W′rec(h), when h is greater than 2.4 nm, η′(h) is less than W′rec(h), and η′(h)/W′rec(h) tends to a stable value of 0.65 as h is close to 50.0 nm.