Effect of band-offsets on the valley polarization properties of WSe₂ lateral homojunctions

We have studied the effect of band-offsets on the valley polarization of lateral homojunctions composed of 1L/n-layer WSe₂ flakes. WSe₂ flakes are transferred onto SiO₂/Si substrates using elastic film assisted micro-mechanical exfoliation. Optical microscopy combined with Raman spectroscopy is used to identify and determine the layer number of 1L/n-layer WSe₂ structures. We worked with naturally occurring 1L/n-layer lateral homojunctions to eliminate the band-offsets resulting from twist angles and stacking order. Spatially-resolved photoluminescence (PL) spectroscopy measurements are performed using a scanning confocal microscope at low temperatures down to 4.2 K and in magnetic fields up to 5T. The intensity and energy position of the different excitation peaks in the PL spectra are mapped to determine the effects of inhomogeneities and band-offsets on the valley polarization properties of the lateral homojunctions. We intend to study the valley Zeeman effect in the lateral homojunctions via polarization-resolved PL spectroscopy. Our work will facilitate in understanding the effects of band alignment on the valley polarization phenomena in TMD homo/heterostructures for valleytronic applications.