The high-performance broadband photodetectors have attracted intensive scientific interests due to their potential applications in optoelectronic systems. Despite great achievements in two-dimensional (2D) materials based photodetectors such as graphene and black phosphorus, obvious disadvantages such as low optical absorbance and instability preclude their usage for the broadband photodetectors with the desired performance. An alternative approach is to find promising 2D materials and fabricate heterojunction structures for multifunctional hybrid photodetectors. In this work, 2D WS 2 /Si heterojunction with a type-II band alignment is formed in situ. This heterojunction device produced a high I on /I off ratio over 10, 6 responsivity of 224 mA/W, specific detectivity of 1.5 × 10 12 Jones, high polarization sensitivity, and broadband response up to 3043 nm. Furthermore, a 4 × 4 device array of WS 2 /Si heterojunction device is demonstrated with high stability and reproducibility. These results suggest that the WS 2 /Si type-II heterojunction is an ideal photodetector in broadband detection and integrated optoelectronic system.

The newly discovered Group-10 transition metal dichalcogenides (TMDs) like PtSe 2 have promising applications in high-performance microelectronic and optoelectronic devices due to their high carrier mobilities, widely tunable bandages and ultrastabilities. However, the optoelectronic performance of broadband PtSe 2 photodetectors integrated with silicon remains undiscovered. Here, we report the successful preparation of large-scale, uniform and vertically grown PtSe 2 films by simple selenization method for the design of a PtSe 2 /Si nanowire array heterostructure, which exhibited a very good photoresponsivity of 12.65 A/W, a high specific detectivity of 2.5 × 10 13 Jones at −5 V and fast rise/fall times of 10.1/19.5 μs at 10 kHz without degradation while being capable of responding to high frequencies of up to 120 kHz. Our work has demonstrated the compatibility of PtSe 2 with the existing silicon technology and ultrabroad band detection ranging from deep ultraviolet to optical telecommunication wavelengths, which can largely cover the limitations of silicon detectors. Further investigation of the device revealed pronounced photovoltaic behavior at 0 V, making it capable of operating as a self-powered photodetector. Overall, this representative PtSe 2 /Si nanowire array-based photodetector offers great potential for applications in next-generation optoelectronic and electronic devices.

Group‐10 transition metal dichalcogenides (TMDs) with distinct optical and tunable electrical properties have exhibited great potential for various optoelectronic applications. Herein, a self‐powered photodetector is developed with broadband response ranging from deep ultraviolet to near‐infrared by combining FA1−xCsxPbI3 perovskite with PdSe2 layer, a newly discovered TMDs material. Optoelectronic characterization reveals that the as‐assembled PdSe2/perovskite Schottky junction is sensitive to light illumination ranging from 200 to 1550 nm, with the highest sensitivity centered at ≈800 nm. The device also shows a large on/off ratio of ≈104, a high responsivity (R) of 313 mA W−1, a decent specific detectivity (D*) of ≈1013 Jones, and a rapid response speed of 3.5/4 µs. These figures of merit are comparable with or much better than most of the previously reported perovskite detectors. In addition, the PdSe2/perovskite device exhibits obvious sensitivity to polarized light, with a polarization sensitivity of 6.04. Finally, the PdSe2/perovskite detector can readily record five “P,” “O,” “L,” “Y,” and “U” images sequentially produced by 808 nm. These results suggest that the present PdSe2/perovskite Schottky junction photodetectors may be useful for assembly of optoelectronic system applications in near future.

The research of ultraviolet photodetectors (UV PDs) have been attracting extensive attention, due to their important applications in many areas. In this study, PtSe 2 /GaN heterojunction is in-situ fabricated by synthesis of large-area vertically standing two-dimensional (2D) PtSe 2 film on n-GaN substrate. The PtSe 2 /GaN heterojunction device demonstrates excellent photoresponse properties under illumination by deep UV light of 265 nm at zero bias voltage. Further analysis reveals that a high responsivity of 193 mA•W-1 , an ultrahigh specific detectivity of 3.8 × 10 14 Jones, linear dynamic range of 155 dB and current on/off ratio of ~ 10 8 , as well as fast response speeds of 45/102 μs were obtained at zero bias voltage. Moreover, this device response quickly to the pulse laser of 266 nm with a rise time of 172 ns. Such high-performance PtSe 2 /GaN heterojunction UV PD demonstrated in this work is far superior to previously reported results, suggesting that it has great potential for deep UV detection.

He is currently focusing on the development of high temperature lubricants from 'soft' ceramic nanoparticles such as layered metal oxides and organosilica networks.catalysis [26] and energy storage. [27] The most widely investigated classes of exfoliated oxide nanosheets are titanates, [28] niobates [29] and titanoniobates, but various other compositions are now also known, as described in more detail below. Table 1. State of the art metal oxide nanosheet compounds. Compound name Exfoliation method Energy application(s) Remarks Ti 0.87 O 2 0.52-Acid-base by TBAOH [19b,32d] Thin film supercapacitors, [49] batteries, [50] piezos, [51] photocatalysis [52] Lateral size up to 100 μm [32d] Fe 0.8 Ti 1.2 O 4 0.8-Acid-base by TBAOH [41d] Photocatalysis [53] Ni 0.4 Ti 1.6 O 4 0.8-Acid-base by TBAOH Photocatalysis [53] Ti 0.91 O 2 0.36−Acid-base by TBAOH [18,54] Photovoltaics, [55] batteries, [56] fuel cells, [57] acid catalysis, [58] photocatalysis [59] Ti 4 O 9 2-Acid-base by TBAOH [37] Batteries, [37,60] fuel cells, [61] photocatalysis [59a,62] MnO 2 0.4-Acid-base by TBAOH [35] Supercapacitors, [35,63] Photovoltaics, [64] batteries, [65] photocatalysis [59a] Mn 1-x Ru x O 2 (x = 0.05 and 0.1) Acid-base by TBAOH [42] Supercapacitors [42] RuO 2 0.2-Acid-base by TBAOH [66] Supercapacitors, [67] fuel cells [68] Ca 2 Nb 3 O 10 − Acid-base by TBAOH [69] Ca 2 Nb 3 O 10−x N y -Acid-base by TBAOH [74] Photocatalysis [74] Ca 2 Na n−3 Nb n O 3n+1 − (n = 4, 5, 6) Acid-base by TBAOH [71] Ca 2-x Sr x Nb 3 O 10 -(x = 0, 0.5, 1, 1.5, 2) Acid-base by TBAOH [75] Photocatalysis [75] Ca 2 Nb 3-x Ta x O 10 -(x = 0.3, 1, 1.5) Acid-base by TBAOH [75] Photocatalysis [75] Ca 2 Nb 3-x Rh x O 10−δ -Acid-base by TBAOH [76] Photocatalysis [76] SrNb 2 O 6 F − Acid-base by TBAOH [69] (Eu 0.56 Ta 2 O 7 ) 2-Acid-base by TBAOH [77] TaO 3 -Acid-base by TBAOH [38] Batteries, [56b] photocatalysis [78] Sr 1.5 Ta 3 O 10 2-Acid-base by TBAOH [79] CaNaTa 3 O 10 2-Acid-base by TBAOH [20] Ca 2 Ta 3 O 10-x N y -Acid-base by TBAOH [44] Photocatalysis [44] Sr 2−x Ba x Ta 3 O 10-y N z -(x = 0.0, 0.5, 1.0) Acid-base by TBAOH [80] Photocatalysis [80] SrLaTi 2 TaO 10 2-Acid-base by TBAOH [20] Ca 2 Ta 2 TiO 10 2-Acid-base by TBAOH [20] Ti (5.2-2x)/6 Mn x/2 O 2 (x = 0.1, 0.2, 0.3, 0.4) Acid-base by TBAOH [81] Ti 1−x−y Fe x Co y O 2 (0 ≤ x ≤ 0.4 and 0 ≤ y ≤ 0.2) Acid-base by TBAOH [82] Cs 4 W 11 O 36 2-Acid-base by TBAOH [83] (MWO 6 ) -(M = Nb, Ta) Acid-base by TBAOH [45] Acid catalysis, [84] photocatalysis [85] NbMoO 6 -Acid-base by TBAOH [86] Acid catalysis [86,87] W 2 O 7 2-Acid-base by TMAOH [45] Photocatalysis [88] (Ti 1.825-x Nb x O 4 ) 0.7-(x = 0-0.03) Acid-base by TBAOH [89] (Ti 1.65 Mg 0.35 O 4 ) 0.7-Acid-base by TBAOH [90] Attempt to make (Ti 1.65 Ni 0.35 O 4 ) 0.7failed [91]Nb 3 O 8 -Acid-base by TBAOH [92] Acid catalysis, [92] photocatalysis [36,93] Nb 6 O 17 4-Acid-base by TBAOH [94] and intercalation of n-propylamine [95] Photovoltaics, [96] photocatalysis [59a][73c,97] TiNbO 5 − Acid-base by TBAOH [71] Batteries, [71] photovoltaics, [71] b...