Tip-enhanced photovoltaic effects in bismuth ferrite
Tip-enhanced photovoltaic effects in bismuth ferrite
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DOI：
10.1038/ncomms1261
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发表时间：
2011-03-01
影响因子：
16.6
通讯作者：
Hesse, Dietrich
中科院分区：
文献类型：
--
作者：
Alexe, Marin;Hesse, Dietrich
多铁BiFeO(3)的光电特性，如超过带隙数倍的大光伏或可切换光电流，最近引起了人们的极大兴趣。这主要是因为它在光伏或光催化装置中的潜在应用。虽然从根本上不同的（从经典半导体）极化相关的电荷分离机制允许无限的光伏，这些材料从来没有被认为是一个可行的替代经典半导体为基础的光伏，因为一个非常低的光转换效率小于10（-4）。本文利用光电原子力显微镜和压电响应力显微镜研究了铋铁氧体BiFeO(3)单晶中的异常光伏效应。我们发现，使用纳米级顶部电极，光激发载流子被有效地收集，外部量子效率提高了7个数量级。这种增强可能为在光伏应用中有效利用反常光伏效应提供一种可行的替代方案。
Photoelectric properties of multiferroic BiFeO(3), such as large photovoltages exceeding several times the bandgap or switchable photocurrents, have recently generated much interest. This is mostly because of potential applications in photovoltaic or photocatalytic devices. Although the fundamentally different (from classical semiconductors) polarization-related charge separation mechanisms allow unlimited photovoltages, these materials have never been considered a viable alternative to classical semiconductor-based photovoltaics because of a very low light conversion efficiency of less than 10(-4). Here we investigate the anomalous photovoltaic effect in bismuth ferrite BiFeO(3) single crystals, using photoelectric atomic force microscopy and piezoresponse force microscopy. We show that using a nanoscale top electrode, the photoexcited carriers are efficiently collected and the external quantum efficiency is enhanced by up to seven orders of magnitude. This enhancement might provide a viable alternative for the effective use of the anomalous photovoltaic effect in photovoltaic applications.