An evaluation by solar simulation of radiation damage in silicon solar cells

From the viewpoint of the space power-systems designer, the most useful data for radiation-damaged solar cells is that of output power as a function of cell voltage, temperature, and radiation. This paper reviews the available results from laboratory radiation experiments where solar simulators were used. The solar cells studied were 1 and 10 ohm-cm n-on-p boron-doped cells, 5 and 10 ohm--cm aluminum-doped cells, and dendritic drift-field cells. Most of the experiments use 1 MeV electrons with some data for 0.5 to 2 MeV electrons and 0.5 to 2.7 MeV protons. Comparisons are made between types of cells on the basis of maximum power output and power at a fixed voltage. A fixed voltage is determined for each cell type using the value of cell voltage at maximum power after a 1 MeV electron fluence of 10
¹⁶
e/cm
²
. There is an apparent lack of agreement among experimental results in the order of 3 or 4 percent, due to spectral variations between simulators. Another reason for the spread in data is attributed to differences that may occur from one group of cells to another, even from the same manufacturer. However, taking this into account, the average power at fixed voltage for the 1 ohm-cm cells is greater than the average for 10 ohm-cm up to a fluence of 5 × 10
¹⁵
e/cm
²
, where a crossover occurs, and the 10 ohm-cm cells became superior.