Luminescent Sm-doped aluminosilicate glass as a substrate for enhanced photoresponsivity of MoS2 based photodetector

Highlights: • Responsivity increase in MoS₂ photodetector via photon recycling and charge transfer. • Luminescent Sm-ASG substrate leads to a 2.3-fold increase in MoS₂ PD responsivity. • Sm-aluminosilicate substrate plays a double role in doping and photoexciting MoS₂ PD. • MoS₂ photoexcitation is enhanced via an efficient photon recycling effect. • Schottky barrier lowering by charge transfer further increases the photoresponsivity. The choice of substrate is crucial for device applications, in particular for atomically thin materials such as monolayer transition metal dichalcogenides. The interaction between the active material and the substrate could be exploited to improve the device performance. In this work, we used a Sm-doped aluminosilicate glass (Sm-ASG) as a substrate for monolayer MoS₂ based photodetector. Due to the strong high-energy emission lines of Sm, Sm-ASG substrate absorbs the incident light and acts as second excitation source compensating the low absorption of the MoS₂ monolayer. On Sm-ASG substrate, the MoS₂ photoresponsivity was increased up to 13,157 AW⁻¹ as compared to 5,740 AW⁻¹ on undoped ASG substrate, under illumination of a monochromatic laser with 520 nm wavelength at a power of 0.2 µW. The significantly enhanced photoresponse, which is amongst the highest reported values for unbiased photoconductors, is attributed to the dual function of Sm-ASG substrate, consisting of a surface charge transfer and an enhanced photoexcitation via a photon recycling effect. Our new approach, based on the simple use of substrate, paves the way for achieving high performance optoelectronic devices.