  An atypical electrical behavior of WS2 nanosheets deposited on Cu electrodes
is reported here. The characteristic Raman peaks at 355cm-1 and 421.8cm-1
confirm the few-layer structure of WS2. The addition of heavy metal ions of ~30
micro Liter on this platform results in non-ohmic behavior in I-V
characteristics, accompanied by a dramatic rise of current from nA to micro
Ampere Additionally, this atypical behavior is found to be reversible.
Subsequent to removal of these ions from the nanosheets, it again exhibits
normal ohmic I-V characteristics. It is envisioned that this unusual
characteristic will pave way for more research in the sensing direction as well
as relevant fields.
