Modeling the light-induced degradation (LID) in silicon due to ASi-Sii-defects

Light-induced degradation (LID) in silicon is one of the major problems that hamper the progress in silicon solar cell technology. We present a method to model the LID kinetics by a differential equation system based on the assumption of charge-state-change-induced configuration changes of the so-called ASi-Sii-defect. Assuming realistic transition rates, we solve this differential equation system under variation of some of the transition rates. It is found that the LID kinetics can in principle be modeled by this approach but care has to be taken if transition rates put into the model are directly extracted from time-dependent carrier lifetime measurements

Observation of a smoothly tunable Dirac point in Ge(BixSb1-x)2Te4

State-of-the-art topological devices require the use of topologically protected surface states to drive electronic transport. In this paper, we examine a tunable topological system, Ge(BixSb1-x)2Te4, for a range of x values from 0 to 1, using a combination of Fourier transform scanning tunneling spectroscopy and angle-resolved photoemission spectroscopy. Our results show that the Dirac point shifts linearly with x, crossing the Fermi energy near x=0.7. This observation of a smoothly tunable, isolated Dirac point crossing through the topological transport regime and having strong linear dependence with substitution can be critical for future topological spintronics applications