Field-Effect Transistor*

We will present the photo response of the few-layered ReSe₂ field-effect transistor fabricated using mechanically exfoliated crystals grown using the chemical vapor transport method. The temperature dependence of the photoconductivity was measured as a function of temperature from 20 K to 300 K using a continuous laser source (λ = 640 nm; E = 1.94eV), over a broad range of illuminating laser power, P_eff (0.2 nW < P_eff < 84 nW). We measured the power dependence of the steady state photocurrent (I_ph) on P_eff (I_ph ~ (P_eff)^γ, where 0.3 ≤ γ ≤ 0.8). The highest responsivity (R) and external quantum efficiency (EQE) obtained from the few-layered ReSe₂ phototransistors at P_eff = 0.2 nW were ~ 2150 A/W and 10⁵ %, respectively. These findings and the temperature dependence of the photoconductivity as a function of gate voltage will be presented.