Unexpected ferromagnetism has been observed in carbon doped ZnO films grown by pulsed laser deposition [H. Pan et al., Phys. Rev. Lett. 99, 127201 (2007)]. In this letter, we introduce carbon into ZnO films by ion implantation. Room temperature ferromagnetism has been observed. Our analysis demonstrates that (1) C-doped ferromagnetic ZnO can be achieved by an alternative method, i.e., ion implantation, and (2) the chemical involvement of carbon in the ferromagnetism is indirectly proven.

The current state of investigations of the problem of providing first mirrors (FMs) for diagnostic systems in a reactor-grade fusion device is summarized. Results obtained in simulation experiments that have been conducted during recent years in several laboratories are presented. Attention is concentrated on two processes that can have an opposite effect but both can lead to degradation of mirror optical properties, namely: sputtering by charge exchange atoms which leads to erosion, and deposition which leads to surface contamination. It is shown in the analysis that when sputtering dominates, mirrors of monocrystalline refractory metals (Mo, W) can have a sufficiently long lifetime even for FMs that have to be located close to the first wall. Similarly, films of low sputtering yield metals on high thermal conductivity substrates (e.g., Rh on Cu) can be used for FMs in locations where the charge exchange flux is reduced to about a tenth of that at the first wall. However, deposition poses a serious threat to the lifetime of FMs but more modeling and experimental investigations are necessary before quantitative conclusions can be reached. Some mitigation methods are possible and these are briefly discussed.

The study is focused on the improvement of the free electron mobility in Al-doped ZnO films grown by reactive pulsed magnetron sputtering. At optimum growth conditions low-absorbing films are obtained with a Hall mobility of $46{\text{cm}}^2{\text{V}}^{-1}{\text{s}}^{-1}$ , a free electron density of $6.0\times {10}^{20}{\text{cm}}^{-3}$ , and an electrical resistivity of $2.26\times {10}^{-4}\Omega \text{cm}$ . The relation between the mobility and free electron density for different growth conditions is discussed in terms of ionized impurity scattering, impurity clustering, and grain boundary limited transport.

The atomic arrangement in $s{p}^2$-dominated carbon (C) and carbon nitride $\left({\mathrm{CN}}_x\right)$ thin films has been studied by Raman spectroscopy as a function of substrate temperature and, in the case of ${\mathrm{CN}}_x$, different N incorporation routes (growth methods). In this way, materials composing graphitelike, fullerenelike (FL), and paracyanogenlike structures have been compared. The results show that each type of arrangement results in a characteristic set of the Raman spectra parameters, which describe the degree of aromatic clustering, bond length, and angle distortion and order in sixfold structures. In the case of C films, the atomic structure evolves with substrate temperature from a disordered network to nanocrystalline planar graphitic configurations, with a progressive promotion in size and ordering of sixfold ring clusters. Nitrogen incorporation favors the promotion of sixfold rings in highly disordered networks produced at low temperatures, but precludes the formation of extended graphiticlike clusters at elevated substrate temperatures $(>700\mathrm{K})$. In the latter case, N introduces a high degree of disorder in sixfold ring clusters and enhances the formation of a FL microstructure. The formation and growth of aromatic clusters are discussed in terms of substrate temperature, N incorporation, growth rate, film-forming sources, and concurrent bombardment by hyperthermal particles during growth.