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2D Bi 2 Te 3 is an emerging semiconducting materials show considerable promise for application in the development of next-generation optoelectronic devices. Especially, broadband photodetection is crucial in various applications, including multispectral imaging and cognition. Therefore, tuning the physical properties of semiconductors and thereby building an efficient p-n homojunction are important for achieving a high-performance photodetection device. However, until now, it is still difficult to construct Bi 2 Te 3 p-n homojunction. In this work, Sb-doped Bi 2 Te 3 was synthesized via chemical vapor deposition, which exhibited typical p-type conduction behavior and a considerable hole mobility of 1.6 cm 2 V −1 s −1 . Benefiting from the built-in electric field, the Bi 2 Te 3 p-n homojunction displays an apparent rectification effect and an extremely low dark current of approximately 10 −14 A. Under illumination, the p-n homojunction, serving as a photodiode, achieved a high power conversion efficiency of 4.65 % and an excellent responsivity of 802.9 A/W. Furthermore, taking advantage of the built-in electric field, the p-n homojunction exhibited broadband self-driving photodetection from 367 to 1550 nm with ultra-high detectivity (3.84 × 10 13 Jones at 520 nm and 8.82 × 10 11 Jones at 1550 nm). This work provides an effective strategy for synthesizing p-type Bi 2 Te 3 and emphasizes the pivotal role of homojunctions for high-performance broadband photodetectors.
Zhang et al. (Tue,) studied this question.