Author(s): Feng, XQ (Feng, Xiaoqiang); He, ZY (He, Zhengyi); Liu, ZD (Liu, Zhiduo); Zhu, W (Zhu, Wei); Zhao, MH (Zhao, Menghan); Yang, SW (Yang, Siwei); Guo, QL (Guo, Qinglei); Chen, D (Chen, Da); Ding, GQ (Ding, Guqiao); Wang, G (Wang, Gang)

Source: ADVANCED OPTICAL MATERIALS Article Number: 2100387 DOI: 10.1002/adom.202100387 Early Access Date: MAY 2021

Abstract: Ultrathin 2D graphene (2D-Gr) sheets have inherently weak absorption characteristics (only 2.3%). Pristine-graphene-based photodetectors therefore have short carrier lifetimes and small Schottky barriers that severely restrict their practical application. In this work, chemical vapor deposition (CVD) and dynamic plasma-assisted CVD (PACVD) are used to grow vertical p-n junctions in situ, which can then be used to form novel near-infrared photodetectors. The directly formed vertical heterostructures feature 0D C3N quantum dots (QDs) in the middle position which acts as nucleation seeds to directly and rapidly grow 3D graphene (3D-Gr) structures that act as the n-type region. The bottom layer consists of a single-crystal 2D-Gr film that forms the p-type region. The large built-in electric field at the interface of the depletion region of the 3D-Gr/2D-Gr vertical p-n junction leads to the rapid separation of any photogenerated electron-hole pairs. Thus, the photodetector exhibits an excellent responsivity of 2.98 x 10(7) A W-1 and a detectivity of 1.04 x 10(13) cm Hz(1/2) W-1 at a wavelength of 1550 nm. The response speed of the photodetector is ultrafast and exceeds that of other vertical/lateral p-n-junction-based photodetectors. Its speed is ascribed to the synergism that exists between the C3N QDs and 3D-Gr due to their unique electron distributions and structural distortions. The research paves the way for a novel class of high-performance graphene-based photodetectors with hybrid architecture.

Accession Number: WOS:000653527800001

ISSN: 2195-1071

Full Text: https://onlinelibrary.wiley.com/doi/10.1002/adom.202100387