In situ construction of PtSe₂/Ge Schottky junction array with interface passivation for broadband infrared photodetection and imaging

Abstract

Infrared (IR) detection is vital for various military and civilian applications. Recent research has highlighted the potential of two‐dimensional (2D) topological semimetals in IR detection due to their distinctive advantages, including van der Waals (vdW) stacking, gapless electronic structure, and Van Hove singularities in the electronic density of states. However, challenges such as large‐scale patterning, poor photoresponsivity, and high dark current of photodetectors based on 2D topological semimetals significantly impede their wider applications in low‐energy photon sensing. Here, we demonstrate the in situ fabrication of PtSe2/Ge Schottky junction by directly depositing 2D PtSe2 films with a vertical layer structure on a Ge substrate with an ultrathin AlOx layer. Due to high quality junction, the photodetector features a broadband response of up to 4.6 μm, along with a high specific detectivity of ~1012 Jones, and operates with remarkable stability in ambient conditions as well. Moreover, the highly integrated device arrays based on PtSe2/AlOx/Ge Schottky junction showcases excellent Mid‐IR (MIR) imaging capability at room temperature. These findings highlight the promising prospects of 2D topological semimetals for uncooled IR photodetection and imaging applications.image

Triply degenerate semimetal PtBi2 as van der Waals contact interlayer in two-dimensional transistor

“…One promising avenue involves the use of semimetals as intermediary layers between 2D transition metal dichalcogenides (TMDs) channels and metal electrodes in transistor designs [17][18][19][20]. This approach is advantageous due to the adjustable work function, which can diminish the Schottky barrier at the contact point [21][22][23][24]. However, current exploration is nascent and only sputtering single elemental semimetals [17,18] and Dirac semimetal ZrTe 2 [19] have been reported.…”

High-Speed Broadband PtSe2/Si 2D-3D Pin Photodetector with a Lightly n-Doped Si Interlayer Based on Single-Oriented PtSe2

“…It shows excellent responsivity, a rapid response time of 14.1/15.4 μs, and a 3 dB frequency of 30 kHz. Li et al reported the fabrication of a PtSe 2 /Ge Schottky junction by directly depositing a 2D PtSe 2 film with a vertical layer structure on a Ge substrate with an ultrathin AlO x layer . This PD demonstrates appealing performance with an outstanding broadband response, a fast response time of 6.7/15.0 μs, and a good 3 dB frequency of 22 kHz.…”

Silicon Waveguide-Integrated Platinum Telluride Midinfrared Photodetector with High Responsivity and High Speed

“…27 A PtSe 2 − AlO x -Ge heterojunction photodetector detecting at 4.6 μm has been presented, but the responsivity is about 1.3 mA/W. 28 A PtTe 2 photodetector can operate at a wavelength of 4 μm, but the responsivity is only 18 μA/W. 29 So, as far as we know, a waveguide-integrated MIR type-II Dirac semimetal photodetector having high responsivity and high speed simultaneously is still absent.…”

“…For the reported photodetector based on PdSe 2 field effect transistor (FET), although a responsivity of 42.1 A/W at 10.6 μm can be obtained, the 3 dB bandwidth is only about 4.7 Hz . A PtSe 2 –AlO x -Ge heterojunction photodetector detecting at 4.6 μm has been presented, but the responsivity is about 1.3 mA/W . A PtTe 2 photodetector can operate at a wavelength of 4 μm, but the responsivity is only 18 μA/W .…”