Observation of abnormal capacitance-frequency behavior in In_0.12Ga_0.88As/GaAs p-i-n superlattice grown at low temperature

Capacitance-frequency measurement is used to study In_0.12Ga_0.88As/GaAs p-i-n superlattice, with superlattice layer grown at 300 °C by molecular-beam epitaxy. Three traps are observed, and their parameters are consistent with those obtained from deep-level transient spectroscopy. Among these three traps, the trap (E_a=0.45±0.02eV, σ=6±4 × 10^-17 cm²) shows an abnormal increase of capacitance with increasing frequency, similar to that observed from the 0.66 eV trap in low-temperature grown GaAs p-i-n structure, suggesting that it is created by the low-temperature growth and is a generation-recombination center. This result also shows that the capacitance-frequency measurement is effective in studying the generation-recombination centers.