Unoccupied electronic states in the energy range from 5 to 20 eV above the Fermi level have been studied in ultrathin films of dimethyl-substituted thiophene–phenylene cooligomers CH₃-phenylene–thiophene–thiophene–phenylene–CH₃ (CH₃–PTTP–CH₃) on polycrystalline gold surfaces of two types: the ex situ Au layer thermally deposited in a special chamber and the in situ Au surface prepared inside an analytical chamber. The film structure is studied by the X-ray diffraction (XRD) method. The formation of a superposition of the amorphous phase and the crystalline phase with period 3.8 nm is discussed. The energy positions of the maxima of the unoccupied electronic states and the character of formation of the boundary potential barrier have been studied by the total current spectroscopy (TCS). The structures of the FSTCS maxima of the 5–7-nm-thick CH₃–PTTP–CH₃ films are not different when using various types of Au substrates and the ZnO semiconductor surface prepared by atomic layer deposition (ALD). As a CH₃–PTTP–CH₃ layer is deposited on the ex situ Au and in situ Au surfaces, the electron work function increases insignificantly (by ~0.1 eV) as the coating thickness increases to 5–7 nm. At such thicknesses of the CH₃–PTTP–CH₃ films, the electron work function is 4.7 ± 0.1 eV in the case of the ex situ Au substrate and 4.9 ± 0.1 eV in the case of the in situ Au substrate. A possible influence of the processes of physicochemical interaction at the boundary between the film and the substrate on the formation of the boundary potential barrier in the structures under study is discussed.

中文翻译：

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多晶金表面上噻吩-苯撑冷单体的超薄膜的未占据电子态

在能量范围从5到20电子伏特的费米能级以上未占据电子态已在超薄的薄膜进行了研究二甲基取代的噻吩-亚苯基共低聚物CH ₃ -亚苯基-噻吩-噻吩-亚苯基- CH ₃（CH ₃ -PTTP-CH ₃）在两种类型的多晶金表面上：热沉积在特殊腔室内的非原位Au层和在分析室内准备的原位Au表面。通过X射线衍射（XRD）方法研究膜结构。讨论了周期为3.8 nm的非晶相和结晶相的叠加。通过总电流谱（TCS）研究了未占据电子态的最大值的能量位置和边界势垒的形成特性。当使用各种类型的Au衬底和通过原子层沉积（ALD）制备的ZnO半导体表面时，5-7 nm厚的CH ₃ -PTTP-CH ₃膜的FSTCS最大值的结构没有不同。作为CH ₃–PTTP–CH ₃层沉积在非原位Au和原位Au表面上，随着涂层厚度增加至5–7 nm，电子功函数显着增加（〜0.1 eV）。在这样的厚度的CH ₃ -PTTP-CH ₃薄膜中，非原位Au衬底的电子功函为4.7±0.1 eV，原位Au衬底的电子功函为4.9±0.1 eV。讨论了在膜和基底之间的边界处的物理化学相互作用过程对所研究结构中边界势垒形成的可能影响。