Di Trolio A, Amore Bonapasta A, Barone C, Leo A, Carapella G, Pagano S, Polimeni A, Testa A M
CNR-Istituto di Struttura della Materia, U.O.S. di Tor Vergata, Via del fosso del cavaliere 100, 00133 Roma, Italy.
CNR-Istituto di Struttura della Materia, Via Salaria Km. 29,300, 00015 Monterotondo St., Roma, Italy.
Phys Chem Chem Phys. 2021 Jan 28;23(3):2368-2376. doi: 10.1039/d0cp06401g.
In the present study, the electrical resistivity (ρ) as a function of the temperature (T) has been measured in polycrystalline ZnO, Co-doped ZnO (ZCO) and H irradiated ZCO (HZCO) samples, in the 300-20 K range. The achieved results show impressive effects of Co doping and H irradiation on the ZnO transport properties. The Co dopant increases the ZnO resistivity at high T (HT), whereas it has an opposite effect at low T (LT). H balances the Co effects by neutralizing the ρ increase at HT and strengthening its decrease at LT. A careful analysis of the ρ data permits to identify two different thermally activated processes as those governing the charge transport in the three materials at HT and LT, respectively. The occurrence of such processes has been fully explained in terms of a previously proposed model based on an acceptor impurity band, induced by the formation of Co-oxygen vacancy complexes, as well as known effects produced by H on the ZnO properties. The same analysis shows that both Co and H reduce the effects of grain boundaries on the transport processes. The high conductivity of HZCO in the whole T-range and its low noise level resulting from electric noise spectroscopy make this material a very interesting one for technological applications.
在本研究中，已在300 - 20 K范围内测量了多晶ZnO、Co掺杂ZnO（ZCO）和H辐照ZCO（HZCO）样品中作为温度（T）函数的电阻率（ρ）。所获得的结果显示了Co掺杂和H辐照对ZnO输运性质的显著影响。Co掺杂剂在高温（HT）下增加了ZnO的电阻率，而在低温（LT）下则有相反的效果。H通过抵消HT下的ρ增加并增强LT下的ρ降低来平衡Co的影响。对ρ数据的仔细分析允许识别出两种不同的热激活过程，分别是在HT和LT下控制这三种材料中电荷输运的过程。根据先前提出的基于由Co - 氧空位复合物形成所诱导的受主杂质带以及H对ZnO性质产生的已知效应的模型，已充分解释了此类过程的发生。相同的分析表明，Co和H都降低了晶界对输运过程的影响。HZCO在整个T范围内的高电导率及其由电噪声光谱法得出的低噪声水平，使得这种材料在技术应用方面非常有趣。
