Photocurrent enhancement of hybrid perovskite CsGeBr3 assisted two-dimensional WS2 nano-flakes based on electron-hole mobility improvement

• Published in: Optical materials 2021-02, Vol.112, p.110754, Article 110754
• Main Authors: Rezaei nik, Y., Reyhani, A., Farjami-Shayesteh, S., Mortazavi, S.Z.
• Format: Article
• Language: English
• Subjects: CsGeBr3 perovskite; Electron-hole separation; Hetero-structure; Photocurrent enhancing; Tungsten disulfide
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2020.110754

The high-performance photocurrent generations of tungsten disulfide Nano-flakes (WS2 NFs) are studied for optoelectronic applications and transistor structures. Moreover, a lead-free inorganic perovskite is formed by replacing of Lead component with germanium at CsPbX3 (X = Cl, Br, I) to achieve an excellent performance of the WS2 based photodetector. The results display that role of the perovskite on the CsGeBr3/WS2 hetero-structure is excellent to enhance photocurrent of the hetero-structure. The external quantum efficiency of the CsGeBr3/WS2 hetero-structure is obtained to be ~151%, and a detectivity is about 4.72 × 108 Jones. Indeed, the external quantum efficiency and detectivity enhance about two times after drop casting of the CsGeBr3 on the WS2 NFs device under green illumination. This finding results from highly efficient photo-excited carrier separation in the interface of the WS2 and CsGeBr3. Drain-source photocurrent in terms of electrical field displays two regimes related to direct and indirect excitons. Indeed, the possibility of exciton indirect formation enhances with increasing of the electrical field due to transfer momentum to electron. •Exciton indirect transition increase with rising up of electrical field.•Devices illustrate that there are two main peaks dependent on the (ΔI)/pIdark.•Type I heterojunction is suggested regarding to shape/location of couriers WS2/CGB.•Electron-hole mobility improvement is dominant effect on WS2/CGB HSs.