The p-n junction formation effect of an Ar+ ion beam on the n-GaAs surface V. M. Mikoushkin, V. V. Bryzgalov, S. Yu. Nikonov, A. P. Solonitsyna and D. E. Marchenko EPL, 122 2 (2018) 27002 Published online: 11 June 2018 DOI: 10.1209/0295-5075/122/27002