The effect of an applied electric field on defect introduction rates in n-type InP [solar cells]

The thermal annealing rates of majority carrier traps in 1 MeV electron irradiated n-type InP solar cells have previously been found to decrease under the effect of an applied field. To detect whether an applied electric field also affects the defect introduction rates, n-type (pin) InP diodes were irradiated with 1 MeV electrons while being subjected to reverse biases ranging from 0 to 6 volts. Deep level transient spectroscopy (DLTS) measurements show the majority carrier defect concentrations increase due to the presence of the applied field over the zero bias rate. The experiment was then repeated with n-type InP solar cells and the degradation in photovoltaic (PV) parameters as a function of electron fluence (φ) was tracked for each applied reverse bias. However, the normalized PV parameters all show a consistent degradation with electron fluence regardless of the strength of the applied reverse bias