The oxidation enhancement photocurrent response in WSe1.95Te0.05 nanosheets

The photocurrent was detected in the WSe1.95Te0.05 with and without surface oxidation. The linear current–voltage relation reveal the WSe1.95Te0.05 nanosheet/Pt ohmic contact. The XPS spectrum reveals the WO3 was formed during the oxidation. The photo responsivity increase from 173 A/W to 442 A/W at 0.5 V after air exposuring in ambient conditions over half year. This value is the highest observed values in two-dimensional transition metal dichalcogenides without artificial treatments. The greatly photocurrent enhancement originated from the incident photo-to-current efficiency (IPCE) enhancement of WO3 at the wavelength of 405 nm.