Low Temperature Synthesis of 2D p-Type α-In 2 Te 3 with Fast and Broadband Photodetection.

2D A 2 III B 3 VI ${\mathrm{A}}_2^{{\mathrm{III}}}{\mathrm{B}}_3^{{\mathrm{VI}}}$ compounds (A = Al, Ga, In, and B = S, Se, and Te) with intrinsic structural defects offer significant opportunities for high-performance and functional devices. However, obtaining 2D atomic-thin nanoplates with non-layered structure on SiO 2 /Si substrate at low temperatures is rare, which hinders the study of their properties and applications at atomic-thin thickness limits. In this study, the synthesis of ultrathin, non-layered α-In 2 Te 3  nanoplates is demonstrated using a BiOCl-assisted chemical vapor deposition method at a temperature below 350 °C on SiO 2 /Si substrate. Comprehensive characterization results confirm the high-quality single crystal is the low-temperature cubic phase α-In 2 Te 3 , possessing a noncentrosymmetric defected ZnS structure with good second harmonic generation. Moreover, α-In 2 Te 3 is revealed to be a p-type semiconductor with a direct and narrow bandgap value of 0.76 eV. The field effect transistor exhibits a high mobility of 18 cm 2 V -1  s -1 , and the photodetector demonstrates stable photoswitching behavior within a broadband photoresponse from 405 to 1064 nm, with a satisfactory response time of τ rise = 1 ms. Notably, the α-In 2 Te 3 nanoplates exhibit good stability against ambient environments. Together, these findings establish α-In 2 Te 3 nanoplates as promising candidates for next-generation high-performance photonics and electronics.