RESEARCH

✔ Background

• The choice of materials that can be grown in conventional epitaxy is limited by the lattice constant of the substrate

• The 2D van der Waals (vdW) material relaxes the lattice constant constraint. 2D/3D vdW heterojunction opens up the possibility of various energy band alignment that could not be achieved with conventional epitaxy

✔ VIS/NIR wideband photodetectors

• Face recognition uses a 940 nm VCSEL, limited by the spectral response of the Si image sensor For eye safety, an image sensor capable of detecting a 1.55 μm long wavelength is required

• MoS2/Ge vdW heterojunction enables visible/near infrared wideband photodetection