Investigation on Semiconductor Physics at Very Low Temperature Using Laser Light as a Probe

点击翻译按钮获取中文摘要

In present day, all laser diodes with quantum well structure have the perfect quality of crystal. So laser chip itself is the best sample for study on solid state quantum physics. This study aims to investigate physics in semiconductor laserr at very low temperature and under magnetic field using output laser light as a probe for inside of laser materials. We expect new phenomena and new physics in a quantum well doide laser under high magnetic field as new interacting system between radiation and quantum transport in low dimension materialWe found new resonance feather in the output of quantum well diode laser driven with constant current at He temperature, while the applied magnetic filed scanned from 0 to 5 Tesla. Almost of all of AlGaInP quantum well lasaer shows this resonance at 0.3-0.4 Tesla where the cyclotron resonance frequncy is very close to cavity spacing of semi-conductor laser. The width of resonance is 0.1-0.15 Tesla at 4 K and its peak is getting lower and its width is … More getting broader as temperature increases. Finally, this resonance disapperars about 20K.The cyclotron motion is confined in the plane of junction due quantum well structure. The polarization of difference frequency between multi-mode oscillation by nonlinear effect is parallel to junction plane. We observed the dependence of reonance peak on the angle between magnetic filed and junction plane. Since its dependence is consistent with theory, we had concluded that this resonance was due to mode locking phenomena of multi-mode oscillation through cyclotron resonance. However, very recently, we found that this kind of resonance is observed below laser oscillation as well as in laser diode under optical excitation. By this observation, the interpretation by mode locking of multi-mode oscillation by cyclotron resonance has been completely denied. We have found another strange resonance with magnetic field in voltage across diode laser driven by constant current. At this stage we do not know the mechanism of two interesting resonance of quantum well laser with magnetic field. We are doing hard experiments to investigate these interesting phenomena. Less