Fig. 4.

Charge funnel effect in HfS₂/HfO₂ engineered devices. a Schematic band diagram of a device subject to strain induced by local oxidation, with V_sd = 0 V, according to the proposed geometry in Fig. 1. b, c Schematic band diagrams of the device under V_sd > 0 and V_sd < 0, respectively. d, e SPCM map of the device under V_sd = ±1 V, respectively. SPCM maps were acquired using λ = 473 nm, P = 150 W cm⁻² at V_bg = +30 V. f Normalised photoresponse along the centre of the channel in the SPCM maps in panels d, e (dots) and simulated curves (solid lines) according to Eq. (1). Inset: optical micrograph of the measured device and measurement diagram. Scale bars are 3 μm