Skip to Main Content
A microcomputer-based DLTS system is presented, in which the microcomputer functions as a signal averager and controller. The system can detect traps deeper than 0.20 eV from the band edges and 103 cm-3 less dense than the intentional dopant concentration. The system was applied to the study of deep traps in liquid-phase epitaxy (LPE) grown GaAs and vapor-phase epitaxy (VPE) grown GaAs0.75P0.25 light-emitting diodes (LEDs). A deep donor level at Ec -0.70 eV and σn=1.3×10-15 cm2 was found in the latter which agreed with capacitance-transients experiments done by another investigator. The electric-field strength was seen to inversely affect the electron capture cross section of this level. A minority-carrier trap reported at Ev+0.15 eV was observed but its energy level was not resolved due to its broad DLTS spectrum peak. The GaAs LED exhibited emission from a deep acceptor level at Eν+0.81 eV and σp=2.2×10-15 cm2, σn=6.8×10-22, and a deep donor level which could not be resolved.