Comparative Analysis of Thin and Thick MoTe2 Photodetectors: Implications for Next-Generation Optoelectronics

Due to its outstanding optical and electronic properties, molybdenum ditelluride (MoTe₂) has become a highly regarded material for next-generation optoelectronics. This study presents a comprehensive, comparative analysis of thin (8 nm) and thick (30 nm) MoTe₂-based photodetectors to elucidate the impact of thickness on device performance. A few layers of MoTe₂ were exfoliated on a silicon dioxide (SiO₂) dielectric substrate, and electrical contacts were constructed via EBL and thermal evaporation. The thin MoTe₂-based device presented a maximum photoresponsivity of 1.2 A/W and detectivity of 4.32 × 10⁸ Jones, compared to 1.0 A/W and 3.6 × 10⁸ Jones for the thick MoTe₂ device at 520 nm. Moreover, at 1064 nm, the thick MoTe₂ device outperformed the thin device with a responsivity of 8.8 A/W and specific detectivity of 3.19 × 10⁹ Jones. Both devices demonstrated n-type behavior, with linear output curves representing decent ohmic contact amongst the MoTe₂ and Au/Cr electrodes. The enhanced performance of the thin MoTe₂ device at 520 nm is attributed to improved carrier dynamics resulting from effective electric field penetration. In comparison, the superior performance of the thick device at 1064 nm is due to sufficient absorption in the near-infrared range. These findings highlight the importance of thickness control in designing high-performance MoTe₂-based photodetectors and position MoTe₂ as a highly suitable material for next-generation optoelectronics.