Sobhan Mushtaq, Xu Qiang, Katoch Akash, Anariba Franklin, Kim Sang Sub, Wu Ping
Entropic Interface Group (EIG), Engineering Product Development, Singapore University of Technology and Design (SUTD), 20 Dover Drive, Singapore.
Nanotechnology. 2015 May 1;26(17):175501. doi: 10.1088/0957-4484/26/17/175501. Epub 2015 Apr 8.
In this paper we investigate O(2) sensing dynamics in BiFeO(3) (BFO) nanofibers at various concentrations and temperatures, by using a combined experiment and computer simulation approach. Samples of pristine BFO, Ni-doped BFO, and Pb-doped BFO nanofibers were prepared. By incorporating Ni and Pb, additional acceptor states are introduced in BFO. Density functional theory calculations show that Ni prefers to substitute Fe site while Pb substitutes Bi site, resulting in a new deep donor originating from Ni interstitial defects, along with oxygen vacancies (V(o)). We find that both the sensing response and recovery time are shorter in samples made of pristine BFO nanofibers than in Ni- and Pb-doped nanofiber samples. We interpret the observed sensing dynamics through charge transport theory of the major (acceptors) and minor (donors) carriers, and found that the minor carrier compensation plays a significant role in determining the response and recovery time of the sensor device. This minor carrier compensation charge transport mechanism will provide new insights into more robust sensor development strategies, and into the research of ion-electron coupling in chemical dynamics of semiconductors.
在本文中，我们采用实验与计算机模拟相结合的方法，研究了不同浓度和温度下BiFeO₃（BFO）纳米纤维中的O(2)传感动力学。制备了原始BFO、Ni掺杂BFO和Pb掺杂BFO纳米纤维样品。通过掺入Ni和Pb，在BFO中引入了额外的受主态。密度泛函理论计算表明，Ni倾向于取代Fe位，而Pb取代Bi位，从而产生了一个源于Ni间隙缺陷的新的深施主，以及氧空位（V(o)）。我们发现，原始BFO纳米纤维制成的样品的传感响应和恢复时间都比Ni和Pb掺杂的纳米纤维样品短。我们通过主要（受主）和次要（施主）载流子的电荷传输理论来解释观察到的传感动力学，并发现次要载流子补偿在确定传感器器件的响应和恢复时间方面起着重要作用。这种次要载流子补偿电荷传输机制将为更稳健的传感器开发策略以及半导体化学动力学中的离子-电子耦合研究提供新的见解。
