PHOTO AND ELECTROCHEMICAL DOPING IN Ge-BASED CHALCOGENIDES S. Rajagopalan, K. Solomon Harshavardhan, Bhanwar Singh and K.L. Chopra J. Phys. Colloques, 42 C4 (1981) C4-911-C4-914 DOI: 10.1051/jphyscol:19814198