Diluted ZnMnTe oxide: a multi‐band semiconductor for high efficiency solar cells

Using oxygen ion implantation and pulsed laser melting, we have synthesized thin films of highly mismatched ternary ( y = 0) and quaternary ( y = 0.12) Zn 1− y Mn y O x Te 1− x alloys with oxygen content in excess of x ∼ 0.01. We show that incorporation of a small amount of isoelectronic oxygen leads to the formation of a narrow, oxygen‐derived band of extended states located well below the conduction band edge of the Zn 1− y Mn y Te matrix. The structure of the conduction band is well described by the anticrossing interaction between O localized states and the extended states of the host semiconductor matrix. As a result the conduction band splits into two subbands with distinctly non‐parabolic dispersion relations. The three absorption edges of this material (∼0.73, 1.83 and 2.56 eV) cover the entire solar spectrum providing a material envisioned for the multi‐band, single junction, high efficiency photovoltaic devices. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)