Measurement of minority carrier lifetime in solar cells from photo-induced open-circuit voltage decay

Comparison between TCAD simulated and measured carrier lifetimes in CMOS photodiodes using the Open Circuit Voltage Decay method

“…The high and low level injection curves usually show two different slopes [4,11,12,18,19], as illustrated in the Fig. 2. …”

“…This function shows a rapid decay followed by a linear slope. With the approximation t greater than IJ r the lifetime is deduced from the gradient of the V(t) vs t waveform, thanks to the following equation [4,12]:…”

“…In order to avoid any perturbation from the oscilloscope [12,19], this experiment was performed with a unity gain buffer (TCL272), providing a very high input impedance of 10 12 Ohm.…”

“…The voltage drop is more important on the sample B due to a higher resistive epitaxy. Then, a region of fast decay can be observed until t=100µs, which could be attributed to a high level injection regime [4,6,[11][12] or to higher decay modes. Indeed, our samples are made of epitaxy and various layers, and the initial fast decay may be interpreted as a redistribution of carrier flows characterized by higher decay modes.…”

“…The OCVD technique was originally introduced by Gossick [7] and Lederhandler [8] in 1955. This technique involves the creation of excess carriers in a PN junction using a brief forward current excitation, and then a monitoring of the voltage across the junction after the abrupt termination of the excitation [7][8][9][10][11][12][13][14]. Then others authors changed the forward current excitation by an optical pulse [12,[15][16][17].…”