Measurement of electron capture probability in quantum well

A new method for measuring the capture probability of excited electrons into quantum wells is presented. Unlike previous techniques, this method is direct, and enables the determination of capture probability as a function of injected electron energy above the well. It is based on an HBT-like structure, with a quantum well as a base. The capture probability is the ratio between base and emitter currents. Two types of bases were studied, a highly p-doped and a low n-doped. The capture by the p⁺ well is much larger than by the n well, probably since the dominant capture mechanism is by electron-hole and electron-hole-plasmon in the former, while in the n doped well the capture is due to a polar optical phonon interaction.