Surface Morphology–Tuned Photocurrent and Carrier Dynamics in MoSe _1.9 Te _0.1 Nanosheets

Abstract In this study, the correlation between surface morphology and optoelectronic response in Te‐doped MoSe 2 (specifically MoSe 1.9 Te 0.1 ) is investigated to elucidate the underlying carrier dynamics governing its photocurrent behavior. X‐ray diffraction and Raman spectroscopy confirm the high crystalline quality of the samples, preservation of hexagonal symmetry, and successful Te incorporation without the formation of secondary phases. X‐ray photoelectron spectroscopy further verifies the substitutional incorporation of Te atoms into the MoSe 2 lattice and indicates minimal surface oxidation. Scanning electron microscopy reveals notable morphological variations among the exfoliated nanosheets, particularly in thickness uniformity and edge roughness. Electrical transport measurements display linear and symmetric I–V characteristics, confirming ohmic contact formation; however, pronounced differences in conductivity are observed across samples with distinct morphologies. Time‐resolved photocurrent measurements under varying illumination powers reveal enhanced responsivity and faster carrier dynamics in samples with smoother surfaces, while rougher samples exhibit sluggish responses due to trap‐mediated recombination. These findings establish a clear link between surface morphology and photocarrier dynamics in MoSe 1.9 Te 0.1 , demonstrating that nanoscale structural quality critically influences macroscopic optoelectronic performance. This work underscores the pivotal role of morphology engineering in optimizing the photodetection capabilities of 2D transition metal dichalcogenides.