Synthesis of wafer-scale WSe2 by WOx selenization on SiO2 / Si substrates

Scalable synthesis of thin tungsten diselenide (WSe
2
) films on 4-inch silicon substrate with 80 nm silicon dioxide (SiO
2
) is demonstrated. Cross-sectional transmission electron microscopy (TEM) reveals good control of WSe
2
layers. Raman spectroscopy confirms high quality crystal of WSe
2
is achieved. Back-gated field-effect transistors (FETs) fabricated on these thin films exhibit p-channel characteristics with a good on/off current ratio larger than 1.2 × 10
²
.