Kim Seong Keun, Kim Shin-Ik, Lim Hyungkwang, Jeong Doo Seok, Kwon Beomjin, Baek Seung-Hyub, Kim Jin-Sang
1] Electronic Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791, South Korea [2] Department of Nanomaterials Science and Technology, Korea University of Science and Technology, Daejeon, 305-333, Republic of Korea.
1] Electronic Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791, South Korea [2] Department of Materials Science and Engineering, Seoul National University, Seoul, 151-744, South Korea.
Sci Rep. 2015 Jan 26;5:8023. doi: 10.1038/srep08023.
The two-dimensional electron gas (2DEG) at the interface between insulating LaAlO3 and SrTiO3 is intriguing both as a fundamental science topic and for possible applications in electronics or sensors. For example, because the electrical conductance of the 2DEG at the LaAlO3/SrTiO3 interface can be tuned by applying an electric field, new electronic devices utilizing the 2DEG at the LaAlO3/SrTiO3 interface could be possible. For the implementation of field-effect devices utilizing the 2DEG, determining the on/off switching voltage for the devices and ensuring their stability are essential. However, the factors influencing the threshold voltage have not been extensively investigated. Here, we report the voltage-induced shift of the threshold voltage of Pt/LaAlO3/SrTiO3 heterostructures. A large negative voltage induces an irreversible positive shift in the threshold voltage. In fact, after the application of such a large negative voltage, the original threshold voltage cannot be recovered even by application of a large positive electric field. This irreversibility is attributed to the generation of deep traps near the LaAlO3/SrTiO3 interface under the negative voltage. This finding could contribute to the implementation of nanoelectronic devices using the 2DEG at the LaAlO3/SrTiO3 interface.
绝缘的LaAlO₃与SrTiO₃界面处的二维电子气（2DEG），无论是作为一个基础科学课题，还是在电子学或传感器领域的潜在应用方面，都备受关注。例如，由于LaAlO₃/SrTiO₃界面处2DEG的电导率可通过施加电场来调节，利用LaAlO₃/SrTiO₃界面处2DEG的新型电子器件便有可能实现。对于利用2DEG的场效应器件而言，确定器件的开/关切换电压并确保其稳定性至关重要。然而，影响阈值电压的因素尚未得到广泛研究。在此，我们报道了Pt/LaAlO₃/SrTiO₃异质结构阈值电压的电压诱导偏移。大的负电压会导致阈值电压出现不可逆的正向偏移。事实上，在施加如此大的负电压后，即使施加很大的正电场，原始的阈值电压也无法恢复。这种不可逆性归因于在负电压下LaAlO₃/SrTiO₃界面附近产生了深陷阱。这一发现可能有助于利用LaAlO₃/SrTiO₃界面处的2DEG来实现纳米电子器件。
