Transient capacitance spectroscopy on large quantum well heterostructures

We report transient capacitancemeasurements on Al x Ga1−x As–GaAs–Al x Ga1 −x As (x∼0.35) double heterojunctions with a large quantum well active region (L z ∼800 Å). It is suggested that the thin GaAs layer acts as a ‘‘giant’’ artificial deep level. It follows then that the band edge discontinuity ΔE c determines the electron emission rates (from the thin layer), thus making it possible for ΔE c to be determined by transient capacitancemeasurements