Investigation of carrier lifetime in 4H-SiC epilayers and lifetime control by electron irradiation

Carrier Lifetime Relevant Deep Levels In SiC

Silicon carbide (SiC) is currently under development for high power bipolar devices such as insulated gate bipolar transistors (IGBTs). A major issue for these devices is the charge carrier lifetime, which, in the absence of structural defects such as dislocations, is influenced by point defects and their associated deep levels. These defects provide energy levels within the bandgap and may act...

Identification and carrier dynamics of the dominant lifetime limiting defect in n 4H-SiC epitaxial layers

Structure of “star” defect in 4H-SiC substrates and epilayers

The structure of the “star” defect in 4H-SiC substrates and its effects on the extended defect structures in the epilayers were studied by molten KOH etching and transmission x-ray topography. Star defects consist of a center region with high densities of threading dislocations (both edge and screw types) and six arms of dislocation arrays extending along <11-20> directions. In addition, multip...

Inelastic carrier lifetime in graphene

We consider hot-carrier inelastic scattering due to electron-electron interactions in graphene as functions of carrier energy and density. We calculate the imaginary part of the zero-temperature quasiparticle self-energy for doped graphene utilizing the G0W and random phases approximations. Using the full dynamically screened Coulomb interaction, we obtain the inelastic quasiparticle lifetimes ...

Spin Lifetime Measurements in MBE-Grown GaAs Epilayers

Electron spin relaxation times in excess of the localized limit have been measured in MBE n-GaAs layers, with the times depending on the doping concentration. We have optically oriented the electrons in the samples, and measured spin lifetimes via luminescence depolarization in a transverse magnetic field (Hanle effect). The lifetimes thus obtained were 14 and 26 ns for samples nominally doped ...