Nanoscale photovoltage mapping in CZTSe/Cu_xSe heterostructure by using kelvin probe force microscopy

Abstract

In the present work, kelvin probe force microscopy (KPFM) technique has been used to study the CZTSe/Cu x Se bilayer interface prepared by multi-step deposition and selenization process of metal precursors. Transmission electron microscopy (TEM) confirmed the bilayer configuration of the CZTSe/Cu x Se sample. Two configuration modes (surface mode and junction mode) in KPFM have been employed in order to measure the junction voltage under illumination conditions. The results show that CZTSe/Cu x Se has small junction voltage of ∼21 mV and the presence of Cu x Se secondary phase in the CZTSe grain boundaries changes the workfunction of the local grain boundaries region. The negligible photovoltage difference between grain and grain boundaries in photovoltage image indicates that Cu x Se phase deteriorates the higher photovoltage at grain boundaries normally observed in CZTSe based device. These results can be important for understanding the role of secondary phases in CZTSe based junction devices.

Nanoscale Probing of Surface Charges in Functional Copper‐Metal Organic Clusters by Kelvin Probe Force Microscopy for Field‐Effect Transistors

“…[55] Here, the lessexplored reign of dielectric is nanoscale probing through the facile Kelvin probe force microscopy (KPFM). [55,56] Although, there are a large variety of samples and devices such as conducting polymer, metals, semiconductor devices, Langmuir-Blodgett films, nanoscale photovoltaic mapping, [57] solar cells, [58] memory devices, [59] electrical properties of the functional materials, [60] surface potential of biomolecules, [61] triboelectric nanogenerators, [62] direct determination of density of states, [63] and so on have been analyzed in recent past through KPFM, and established the corresponding contact potential analysis. [64,65] As well, KPFM, also has adequate strength for broad applications in investigating the charge dynamics in ferroelectric and dielectric systems.…”