Huber Silvia, Mardare Cezarina Cela, Mardare Andrei Ionut, Kleber Christoph, Hassel Achim Walter
Christian Doppler Laboratory for Combinatorial Oxide Chemistry at the Institute for Chemical Technology of Inorganic Materials (TIM), Johannes Kepler University Linz Altenberger Str. 69 4040 Linz Austria.
TIM, Johannes Kepler University Linz Altenberger Str. 69 4040 Linz Austria
RSC Adv. 2019 Nov 1;9(61):35579-35587. doi: 10.1039/c9ra01758e. eCollection 2019 Oct 31.
Doped ZnO thin films on ITO substrates were prepared by reactive co-sputtering of ZnO and several dopant metals, namely Al, Mn, Ti, W or Zr. To elucidate the influence of the dopant, morphological and compositional investigations were performed applying SEM/EDX, XRD and AFM. The optical band gaps of the materials were determined by UV-VIS measurements and the subsequent analysis of the derived Tauc plots. SKP (Scanning Kelvin Probe) measurements were performed under alternating illumination periods in order to measure the CPD (contact potential difference) response on UV irradiation; effective donor concentrations were calculated from the SKP results. The obtained X-ray diffractograms revealed that W : ZnO is amorphous, whereas all other dopants form crystalline structures with diffraction angles shifted towards lower values. SEM and AFM imaging revealed a significant influence of the dopant on the film morphology. The optical band gap values are in the range of the ZnO value (∼3.30 eV), with the lowest value of 3.29 eV being measured for Mn : ZnO. An exception was found for W : ZnO, which exhibits significant band gap widening reaching 4.35 eV. The effective donor concentrations are low for all samples under dark conditions, whereas they showed enhanced values under illumination. The sensitivity of all materials towards illumination makes them promising candidates for future research activities in the field of photovoltaics.
通过对氧化锌（ZnO）与几种掺杂金属（即铝（Al）、锰（Mn）、钛（Ti）、钨（W）或锆（Zr））进行反应性共溅射，在氧化铟锡（ITO）衬底上制备了掺杂的ZnO薄膜。为了阐明掺杂剂的影响，应用扫描电子显微镜/能谱仪（SEM/EDX）、X射线衍射仪（XRD）和原子力显微镜（AFM）进行了形态学和成分研究。通过紫外-可见（UV-VIS）测量以及对所得陶克（Tauc）图的后续分析来确定材料的光学带隙。在交替光照周期下进行扫描开尔文探针（SKP）测量，以测量紫外照射下的接触电势差（CPD）响应；根据SKP结果计算有效施主浓度。所得的X射线衍射图表明，W:ZnO是非晶态的，而所有其他掺杂剂形成晶体结构，其衍射角向较低值偏移。扫描电子显微镜和原子力显微镜成像显示掺杂剂对薄膜形态有显著影响。光学带隙值在ZnO值（约3.30 eV）范围内，Mn:ZnO的最低值为3.29 eV。W:ZnO是个例外，其显示出显著的带隙拓宽，达到4.35 eV。在黑暗条件下，所有样品的有效施主浓度都很低，而在光照下它们的值有所增加。所有材料对光照的敏感性使其成为光伏领域未来研究活动的有前景的候选材料。
