DIRECT ANALYSIS OF THE PHOTOCURRENT TRANSIENT IN SEMI-INSULATING GAAS

We report the results of a detailed analysis of digitally recorded photocurrent transients in semi-insulating GaAs. These generally consist of a sum of exponentials with decay time constants that can be uniquely determined from the fitting procedure. The obtained values for these time constants are more reliable than those determined from the conventional double gate method, where some questionable approximations are always included. At high temperatures and under a strong background illumination, we observed photocurrent transients with an inverted derivative signal. This signal inversion can be understood if we take into account the background current. © 1990.