Bernard Dam , Fahimeh Nafezarefi , Diana Chaykina , Giorgio Colombi , Ziying Wu , Stephan W.H. Eijt , Shrestha Banerjee , Gilles de Wijs , Arno Kentgens
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引用次数: 0
摘要
稀土氧氢化物(REH3-2xOx)在能量超过带隙的光子照射下会产生光致暗化现象。我们认为薄膜分为富氢区和贫氢区。在光照下,激发的电子会还原三价阳离子,导致富氢实体中的绝缘体向金属转变。这些小的金属氧氢团簇是光吸收增强的原因。在周围的半导体基体中,光激发诱导了从 p 型到 n 型导电性的转变。这种持续的光电导现象是由于氢化物离子捕获了空穴。因此,费米级上升到传导带以上,诱发了伯斯坦-莫斯效应,使导电率大幅提高。
Perspective on the photochromic and photoconductive properties of Rare-Earth Oxyhydride thin films
Rare-Earth oxyhydrides (REH3-2xOx) are characterized by photodarkening when illuminated by photons having an energy exceeding that of the band gap. We propose that the film is segregated in hydrogen rich and hydrogen poor areas. Upon illumination, the excited electrons reduce the three-valent cations inducing an insulator to metal transition in the hydrogen rich entities. These small metallic oxyhydride clusters are responsible for the enhanced optical absorption. In the surrounding semiconductor matrix the photoexcitation induces a transition from p to n-type conductivity. This persistent photoconductivity is due to trapping of the holes by hydride ions. As a result, the Fermi level rises above the conduction band inducing a Burstein-Moss effect and a large increase in the conductivity.
期刊介绍:
Solar Energy Materials & Solar Cells is intended as a vehicle for the dissemination of research results on materials science and technology related to photovoltaic, photothermal and photoelectrochemical solar energy conversion. Materials science is taken in the broadest possible sense and encompasses physics, chemistry, optics, materials fabrication and analysis for all types of materials.