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用溶胶–凝胶法制备的钴掺杂氧化锌薄膜在不同气氛下退火后均显示室温铁磁性,并且具有不同的载流子浓度。通过对薄膜进行电、磁、光性能及微结构的系统表征,建立了磁性能与载流子浓度之间的关联。研究表明:在氧气和氧氮混合气氛以及氧氩气氛下,退火的样品均具有室温铁磁性。相对于氧氮混合气氛,300K,在无氮气氛退火的样品具有更低的矫顽力,更高的剩磁及大的电子浓度。光致发光谱研究表明:氧氮混合气氛下,退火的样品中存在No受主,这是样品电子浓度及铁磁性下降的原因;因此,体系的铁磁性来源于电子间接机制,使通过控制载流子浓度来调节钴掺杂氧化锌稀磁半导体的铁磁性能成为可能。
The cobalt-doped zinc oxide films prepared by sol-gel method show room-temperature ferromagnetism after annealing at different atmospheres and have different carrier concentrations. The relationship between magnetic properties and carrier concentration was established by systematically characterizing the films by means of electrical, magnetic and optical properties and microstructures. The results show that the annealed samples have room-temperature ferromagnetism in oxygen and oxygen-nitrogen mixed atmosphere and oxygen-argon atmosphere. Compared with the mixed oxygen and nitrogen atmosphere, the samples annealed at 300K in the nitrogen-free atmosphere have lower coercivity, higher remanence and large electron concentration. The results of photoluminescence spectroscopy show that there is No acceptor in the annealed sample in the mixed atmosphere of oxygen and nitrogen, which is the reason for the decrease of electron concentration and ferromagnetism in the sample. Therefore, the ferromagnetism of the system originates from the indirect electron mechanism, It is possible to adjust the ferro-magnetic properties of the cobalt-doped zinc oxide diluted magnetic semiconductors by the concentration of the target.