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II-VI和III-V族高失配合金半导体是新型高效中间带太阳电池的优选材料体系,但中间带的形成及其能带调控等关键问题仍未得到有效解决.采用氧离子注入方式,在非平衡条件下对碲化锌(Zn Te)单晶材料实现了等电子掺杂,深入研究了离子注入对Zn Te:O材料的微观结构和光学特性的影响.研究表明:注入合适浓度的氧离子(2.5×1018cm-3)将会形成晶格应变,并诱导1.80 e V(导带下0.45 e V)中间带的产生;而较高浓度(2.5×1020cm-3)的氧离子会导致Zn Te注入层表面非晶化,并增强与锌空位相关的深能级(～1.6 e V)发光.时间分辨光致发光结果显示,离子注入诱导形成的中间带主要是和氧等电子陷阱束缚的局域激子发光有关,载流子衰减寿命较长(129 ps).因此,需要降低晶格紊乱度和合金无序,实现电子局域态向扩展态的转变,从而有效调控中间带能带结构.
II-VI and III-V high-mismatched alloy semiconductors are the preferred material systems for the new high-efficiency intermediate solar cells, but the key issues such as the formation of the intermediate band and its band regulation have not yet been effectively solved.Using ion implantation, Electron doping of zinc telluride (ZnTe) single crystal material was carried out under non-equilibrium condition, and the effect of ion implantation on the microstructure and optical properties of ZnTe: O material was studied. The results show that: Oxygen ions (2.5 × 10 18 cm -3) will form a lattice strain and induce the generation of an intermediate band of 1.80 eV (0.45 eV below the conduction band); oxygen ions of higher concentration (2.5 × 10 20 cm -3) cause The surface of ZnTe implanted layer is amorphized and enhances the deep level (-1.6 eV) luminescence related to zinc vacancies.The time-resolved photoluminescence shows that the intermediate band induced by ion implantation is mainly bound to oxygen and other electron traps Of the local exciton luminescence, the carrier decay life longer (129 ps). Therefore, the need to reduce lattice disorder and alloy disorder, to achieve the electronic state transition to the extended state, so as to effectively control the middle band energy Belt structure.