The role of point defects and arsenic precipitates in carrier trapping and recombination in low-temperature grown GaAs

GaAs epilayers were grown with a wide range of excess arsenic concentrations and subjected to various anneals to study the role of the point defects and arsenic precipitates in carrier trapping and recombination. Prior to anneal, the point defects rapidly trap photogenerated electrons and holes—usually on subpicosecond time scales. However, full electron-hole recombination occurs on a significantly longer time scale. After anneal, the full electron-hole recombination lifetime appears to be greatly reduced, indicating that the arsenic precipitates play a significant role.