Advanced characterisation techniques - UHasselt

In order to address the local photovoltaic properties EBIC and advanced SPM-techniques can be used.

EBIC (electron beam induced current) will be used for the visualisation of structures related with built in potential parameters. These EBIC studies are carried out with a wafer prober measurement system.

Local electrical and photovoltaic properties can be studied using advanced SPM-techniques such as Conductive AFM (C-AFM), Electric Force Microscopy (EFM) and Kelvin Probe Force Microscopy (KPFM) with spatial resolution down to 20 nm.   C-AFM allows a simultaneous local mapping of topographical and electrical properties of conductive and semiconducting structures, with the possibility to perform local spectroscopy (IV-curves) to investigate the local transport properties.  The C-AFM measurements can be performed in a glovebox system in combination with a solar simulator.

To study the electronic structure, absorption coefficients, external quantum efficiency (EQE) and defect levels of the semiconductor films or photovoltaic devices, highly sensitive photothermal (photothermal deflection spectroscopy-PDS) and photocurrent based techniques (Fourier-transform photocurrent spectroscopy-FTPS/Constant photocurrent method-CPM) are proposed.  These techniques exhibit superior sensitivity over transmission/reflection spectroscopy (T/R), usually employed to measure the optical absorption of thin film materials.