The influence of the exciton non-radiative recombination in silicon on the photoconversion efficiency. 1. Long Shockley–Read–Hall lifetimes

By comparison of the experimental dependence of bulk lifetime in silicon on the doping and excitation levels with theoretical calculations, it has been shown that a new recombination channel becomes operative when Shockley–Read–Hall lifetime is below 20 ms and the density of doping impurities or the excess electron-hole pair density is of the order of 10¹⁶ cm⁻³. This recombination mechanism is related to the non-radiative exciton Auger recombination assisted by the deep impurities in the bulk. The influence of non-radiative exciton recombination on the photoconversion efficiency in solar cells has been analyzed. It has been shown that the shorter the Shockley–Read–Hall lifetime, τSHR, the stronger its effect. In particular, for τSHR = 100 μs, this recombination channel leads to the reduction of the photoconversion efficiency by 5.5%

Project of VEPP-2000 electron-positron collider

The status of VEPP-2M collider is presented. Implementation of Round Colliding Beams (RCB) concept in the new collider VEPP-2M is outlined, potential advantages of RCB over the flat colliding beams are discussed. The main desing parameters and features of this VEPP-2000 collider are reported

Influence of non-radiative exciton recombination in silicon on photoconversion efficiency. 2. Short Shockley–Read–Hall lifetimes

The influence of non-radiative exciton recombination (NRER) on the photoconversion efficiency in silicon solar cells with short Shockley–Read–Hall lifetimes τSRH has been studied. It has been shown that the efficiency reduction due to this effect is the stronger the shorter τSRH. The influence of NRER is most evident when the NRER time becomes shorter than τSRH. At sufficiently short τSRH, NRER substantially limits the optimal base doping levels of silicon solar cells, at which the photoconversion efficiency is maximal