Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

The two-dimensional materials with direct band gap are attractive for optoelectronics operated in the visible and near infrared spectral range. The number of new van der Waals crystals increases systematically but the doping and the modification of their optoelectronic properties remain challenging. Here we present the tuning of the fundamental properties of different 2D mono- and dichalcogenides using millisecond range flash lamp annealing (FLA) in the controlled atmosphere. Those investigated 2D flakes are made by mechanical exfoliation onto the SiN/Si substrates. The change of internal properties of 2D chalcogenides is monitored by micro-Raman, photoluminescence and photoreflectance spectroscopies as well as conductive atomic force microscope (c-AFM). Using ms-range FLA in N2 ambient the transition metal dichalcogenides are stable up to the annealing at 1200 oC, while upon high temperature annealing the group IV-dichalcogenides can be reduced to monochalcogenides which opens new route for the fabrication of heterostructures. The formation of SnSe/SnSe2 heterostructures is proven by micro-Raman spectroscopy and current-voltage characteristic obtained by c-AFM measurements.