Yu K M, Walukiewicz W, Wu J, Shan W, Beeman J W, Scarpulla M A, Dubon O D, Becla P
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Phys Rev Lett. 2003 Dec 12;91(24):246403. doi: 10.1103/PhysRevLett.91.246403. Epub 2003 Dec 11.
We report the realization of a new mult-band-gap semiconductor. Zn(1-y)Mn(y)OxTe1-x alloys have been synthesized using the combination of oxygen ion implantation and pulsed laser melting. Incorporation of small quantities of isovalent oxygen leads to the formation of a narrow, oxygen-derived band of extended states located within the band gap of the Zn(1-y)Mn(y)Te host. When only 1.3% of Te atoms are replaced with oxygen in a Zn0.88Mn0.12Te crystal the resulting band structure consists of two direct band gaps with interband transitions at approximately 1.77 and 2.7 eV. This remarkable modification of the band structure is well described by the band anticrossing model. With multiple band gaps that fall within the solar energy spectrum, Zn(1-y)Mn(y)OxTe1-x is a material perfectly satisfying the conditions for single-junction photovoltaics with the potential for power conversion efficiencies surpassing 50%.
我们报道了一种新型多带隙半导体的实现。通过氧离子注入和脉冲激光熔化相结合的方法合成了Zn(1-y)Mn(y)OxTe1-x合金。掺入少量等价氧会导致在Zn(1-y)Mn(y)Te主体的带隙内形成一个窄的、由氧衍生的扩展态能带。当在Zn0.88Mn0.12Te晶体中仅1.3%的Te原子被氧取代时，所得的能带结构由两个直接带隙组成，带间跃迁分别约为1.77和2.7 eV。能带结构的这种显著变化可以通过能带反交叉模型很好地描述。由于多个带隙落在太阳能光谱范围内，Zn(1-y)Mn(y)OxTe1-x是一种完全满足单结光伏条件的材料，其功率转换效率有可能超过50%。
