The origin of anomalous muonium in semiconductors

The origin of muonium defect centers in semi-insulating GaAs has been studi ed using newly developed mu SR techniques employing alternating electric fi elds. This technique prevents the accumulation of near-surface charges whic h may screen the external field. Thr screening effect was tested at ISIS by the measurements of the current induced by muon beam. suppression of anoma lous muonium signal with electric field suggests that muonium formation pro ceeds via transport of excess electrons from the ionization track to the mu ons. (C) 2000 Elsevier Science B.V. All rights reserved.