Time-resolved photo-assisted Kelvin probe force microscopy on Cu(In,Ga)Se2 solar cells

Abstract

Abstract Photo-assisted Kelvin probe force microscopy (P-KFM) is very useful for examining photovoltaic characteristics especially on solar cells, although a time resolution in the conventional P-KFM was not sufficient for investigating carrier dynamics in time domain. In this study, we have introduced both an intermittent bias application method and a pump-probe method into P-KFM to realize time-resolved measurements at μsec order. Then the photo-carrier dynamics in Cu(In,Ga)Se2 solar cells with different Ga compositions have been examined by our time-resolved P-KFM through direct observation of rising and decay waveforms of the photovoltage induced by the pulsed light illumination and through two-dimensional observation of photovoltage distributions at various time intervals between the optical pump and electrical probe pulses.