High-quality large-sized hexagoal WSe2 crystals can be grown on dielectric substrates using atmospheric chemical vapor deposition in the presence of hydrogen gas. These hexagonal crystals (lateral width >160 um) have a carrier mobility of 100 cm(2) V-1 s(-1) and a photoresponsivity of approximate to 1100 mA W-1, which is comparable to that of exfoliated flakes. [GRAPHICS] .