We report the energy landscape of an upcoming solar cell material series, namely, silver-bismuth-iodide rudorffites $\left(A_m{B}_n{X_m}_{+3n}\right)$. We formed the compounds through compositional engineering and characterized them. We employed Kelvin probe force microscopy (KPFM) to derive the surface work function and thereby the Fermi energy; scanning tunneling spectroscopy (STS), on the other hand, provided conduction and valence band edges with respect to the Fermi energy of the rudorffites. By combining KPFM and STS studies, we obtained a composition-dependent tuning of the Fermi energy in rudorffite thin films, namely, ${\mathrm{Ag}}_3\mathrm{Bi}{\mathrm{I}}_6$, ${\mathrm{Ag}}_2\mathrm{Bi}{\mathrm{I}}_5$, $\mathrm{AgBi}{\mathrm{I}}_4$, $\mathrm{Ag}{\mathrm{Bi}}_2{\mathrm{I}}_7$, and $\mathrm{Ag}{\mathrm{Bi}}_3{\mathrm{I}}_{10}$ with a gradual change in electronic conductivity from $p$ to $n$ type. While such behavior has been correlated to point defects, which are possible to form in the different members of the rudorffite series, we more importantly show that a combination of KPFM and STS studies can provide the complete energy landscape of a semiconductor.

中文翻译：

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银-铋-碘化物rudorffite的能量景观：结合扫描隧道光谱和开尔文探针力显微镜

我们报告了即将推出的太阳能电池材料系列的能源格局，即银-铋-碘化物 rudorffites $\left({\mathrm{一种}}_{米}{乙}_n{X_{米}}_{+3n}\right)$. 我们通过成分工程形成化合物并对其进行表征。我们采用开尔文探针力显微镜 (KPFM) 来推导表面功函数，从而推导出费米能量；另一方面，扫描隧道光谱 (STS) 提供了关于 rudorffite 的费米能​​量的导带和价带边缘。通过结合 KPFM 和 STS 研究，我们获得了 rudorfite 薄膜中费米能量的组成依赖调谐，即，${银}_3双{\mathrm{一世}}_6$, ${银}_2双{\mathrm{一世}}_5$, $\mathrm{银铋}{\mathrm{一世}}_4$, $银{双}_2{\mathrm{一世}}_7$， 和 $银{双}_3{\mathrm{一世}}_{10}$ 随着电子电导率的逐渐变化 $磷$ 到 $n$类型。虽然这种行为与点缺陷相关，点缺陷可能在 rudorfite 系列的不同成员中形成，但我们更重要的是表明，KPFM 和 STS 研究的结合可以提供半导体的完整能量图谱。