The negative differential resistance (NDR) is closely related to the pulse and compliance current (CC) but not ferroelectric polarization in BaTiO 3 /Nb:SrTiO 3 heterojunctions. The NDR feature shows an opposite trend on the positive (+V P ) and negative pulse (−V P ) and the same trend on pulse amplitude and width while maintaining the same polarity. When the applied pulse was small or short, the NDR characteristics are almost not influenced. With increase of the +V p (−V p ) amplitude or width, NDR enhances (reduces) while shifting to a smaller (bigger) negative bias voltage (−V b ), and the low resistance state (LRS) reduces (enhances) while the high resistance state (HRS) almost remains unchanged. Furthermore, as CC increases, the NDR enhances markedly and barely shifts, while the LRS and HRS almost remain unchanged. Interestingly, the NDR location and LRS exhibit the same dependence on the amplitude/width of ±V p and CC. The above behaviors of NDR can be attributed to the variance of oxygen vacancy (V o ) concentration and depletion layer width. It is beneficial for the development of NDR devices.

The negative differential resistance (NDR) in ZnO/Nb:SrTiO3 heterojunctions is found to be strongly dependent on negative pulse amplitude/width and compliance current. When a small or short negative pulse is applied, the NDR feature remains almost the same. With the negative pulse amplitude or width increasing, the NDR feature gradually fades down and shifts to a larger negative bias. Meanwhile, the NDR intensity increases markedly without significant shift with increase of the compliance current. Interestingly, the low‐resistance state and NDR location are found to exhibit exactly the same trend when varying the negative pulse amplitude, width, and compliance current. The dependence of the NDR intensity and location on the pulse amplitude/width and compliance current can be well understood from the variance of concentration of ionized oxygen vacancies and the depletion layer width, respectively. This will promote the application of NDR devices.