低温ZnSe/ZnS多量子阱光学双稳态

我们在77K温度下,观察了ZnSe/ZnS多量子阱的激光吸收及激子带展宽现象。在不同的激发波长处进一步得到了增强吸收双稳和色散型双稳态。非线性机制为激子带展宽。     

Energy relaxation of light holes in InAs.15Sb.85/InSb multiple quantum wells

The energy relaxation rate of light in-plane holes in InAs_.15Sb_.85/InSb quantum wells has been measured using a Shubnikov-de Haas technique. In this Type II system, the holes reside in the InSb layers; strain reverses the heavy-light hole ordering and thus light holes are the charge carriers. The samples consist of 20 to 100 InAs_.15Sb_.85/InSb periods 100Å/200Å thick. The InAsSb barriers are doped with Be. The total carrier concentration p ≈ 1×10¹¹ cm⁻² is obtained from Hall data. Shubnikov-de Haas oscillation amplitudes are measured and used to determine the light hole temperature for a given applied power. The steady state power per carrier is equated to the energy relaxation rate to determine the carrier temperature T_H. The measured rate for low electric fields is proportional to T_Hⁿ-T_Lⁿ with n ≈ 3.2 and 2.5 for two different samples. These data are compared with theory and experiment for light holes in InGaAs/GaAs quantum wells.     

Energy relaxation in GaInAs/AlInAs heterojunctions and GaAs/AlGaAs multiple quantum wells

We have studied electron energy relaxation in GaInAs/AlInAs heterojunctions and GaAs/AlGaAs multiple quantum wells using mobility measurements as a function of electric field and temperature, in the range 3K to 300K. The results in the range 3 to 20K show a power loss rate which is dependent on (T_e − T_l), suggesting that the energy relaxation occurs through acoustic phonon scattering. At electron temperatures greater than 20K, the experimental results are modelled using a standard expression for polar optical phonons. This modelling yields 30meV and 31meV for the polar optical phonon energy in GaAs and InGaAs respectively.