Defect Reactions Responsible for Boron-Oxygen Degradation in Crystalline Silicon Photovoltaics

Autor: De Guzman, J.A.T., Markevich, V.P., Peaker, A.R., Vaqueiro-Contreras, M., Coutinho, J., Crowe, I.F., Hawkins, I., Hammersley, S., Halsall, M.P.
Jazyk: angličtina
Rok vydání: 2020
Předmět:
DOI: 10.4229/eupvsec20202020-2ao.5.2
Popis: 37th European Photovoltaic Solar Energy Conference and Exhibition; 145-151
Light-induced degradation of silicon solar cells containing boron and oxygen impurity atoms (BO-LID) has been linked recently with structural transformations of the defect consisting of a substitutional boron atom and two interstitial oxygen atoms - BsO2. An atomistic model and configuration-coordinate diagram of the BsO2 defect have been proposed (M. Vaqueiro-Contreras et al, J. Appl. Phys. 125 (2019) 185704). In the present work, we have studied the transformations of the BsO2 defect between configurations with different recombination activity in n+-p-p+ diodes fabricated from Si:B+O materials with different boron concentrations using deep-level transient spectroscopy (DLTS) and Laplace DLTS. The transformations have been initiated either by minority carrier injection (MCI) by forward biasing the diodes (BO degradation) or by increasing the temperature of the diodes above 313 K in dark after the MCI treatments (BO annealing). The values of energy barriers for the forward and back processes have been determined and found to be consistent with those known from literature for BO-LID. Further, we have compared the defect reactions degrading the boron-oxygen system with similar reactions in material doped with gallium, indium or aluminium and discuss possible explanations of the reduced degradation in samples doped with group-III elements other than boron.
Databáze: OpenAIRE