Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin, Germany.
Phys Rev Lett. 2010 May 14;104(19):196602. doi: 10.1103/PhysRevLett.104.196602.
The electronic structure of grain boundaries in polycrystalline Cu(In,Ga)Se2 thin films and their role on solar cell device efficiency is currently under intense investigation. A neutral barrier of about 0.5 eV has been suggested as the reason for the benign behavior of grain boundaries in chalcopyrites. Previous experimental investigations have in fact shown a neutral barrier but only a few 10 meV high, which cannot be expected to have a significant influence on the solar cell efficiency. Here we show that a full investigation of the electrical behavior of charged and neutral grain boundaries shows the existence of an additional narrow neutral barrier, several 100 meV high, which is tunneled through by the majority carriers but is sufficiently high to explain the benign behavior of the grain boundaries.
多晶 Cu(In,Ga)Se2 薄膜晶界的电子结构及其对太阳能电池器件效率的影响目前受到广泛关注。有人提出，在黄铜矿中晶界的良性行为是由于存在一个约 0.5eV 的中性势垒。之前的实验研究实际上已经表明存在一个中性势垒，但只有几个 10meV 高，这不能期望对太阳能电池效率有显著影响。在这里，我们表明，对带电和中性晶界的电行为的全面研究表明，存在一个额外的狭窄中性势垒，几个 100meV 高，大多数载流子可以通过这个势垒，但这个势垒足够高，可以解释晶界的良性行为。
