Metal–organic frameworks (MOFs) are emerging as an appealing class of highly tailorable electrically conducting materials with potential applications in optoelectronics. Yet, the realization of their proof‐of‐concept devices remains a daunting challenge, attributed to their poor electrical properties. Following recent work on a semiconducting Fe3(THT)2(NH4)3 (THT: 2,3,6,7,10,11‐triphenylenehexathiol) 2D MOF with record‐high mobility and band‐like charge transport, here, an Fe3(THT)2(NH4)3 MOF‐based photodetector operating in photoconductive mode capable of detecting a broad wavelength range from UV to NIR (400–1575 nm) is demonstrated. The narrow IR bandgap of the active layer (≈0.45 eV) constrains the performance of the photodetector at room temperature by band‐to‐band thermal excitation of charge carriers. At 77 K, the device performance is significantly improved; two orders of magnitude higher voltage responsivity, lower noise equivalent power, and higher specific detectivity of 7 × 108 cm Hz1/2 W−1 are achieved under 785 nm excitation. These figures of merit are retained over the analyzed spectral region (400–1575 nm) and are commensurate to those obtained with the first demonstrations of graphene‐ and black‐phosphorus‐based photodetectors. This work demonstrates the feasibility of integrating conjugated MOFs as an active element into broadband photodetectors, thus bridging the gap between materials' synthesis and technological applications.
A highly promising route to scale millions of qubits is to use quantum photonic integrated circuits (PICs), where deterministic photon sources, reconfigurable optical elements, and single-photon detectors are monolithically integrated on the same silicon chip. The isolation of single-photon emitters, such as the G centers and W centers, in the optical telecommunication O-band, has recently been realized in silicon. In all previous cases, however, single-photon emitters were created uncontrollably in random locations, preventing their scalability. Here, we report the controllable fabrication of single G and W centers in silicon wafers using focused ion beams (FIB) with high probability. We also implement a scalable, broad-beam implantation protocol compatible with the complementary-metal-oxide-semiconductor (CMOS) technology to fabricate single telecom emitters at desired positions on the nanoscale. Our findings unlock a clear and easily exploitable pathway for industrial-scale photonic quantum processors with technology nodes below 100 nm.
The field of two‐dimensional (2D) materials has stimulated considerable interest in the scientific community. Owing to quantum confinement in one direction, intriguing properties have been reported in 2D materials that cannot be observed in their bulk form. The advent of semiconducting 2D materials with a broad range of electronic properties has provided fascinating opportunities to design and configure next‐generation electronics. One such emerging class is the family of III‐VI monochalcogenides, the two prominent members of which are indium selenide (InSe) and gallium selenide (GaSe). In contrast to transition metal dichalcogenides, their high intrinsic mobility and the availability of a direct bandgap at small thicknesses have attracted researchers to investigate the underlying physical phenomena as well as their technological applications. However, the sensitivity of InSe and GaSe to environmental influences has limited their exploitation in functional devices. The lack of methods for their scalable synthesis further hinders the realization of their devices. This review article outlines recent advancements in the synthesis and understanding of the charge transport properties of InSe and GaSe for their integration into technological applications. A detailed summary of the improvements in the device structure by optimizing extrinsic factors such as bottom substrates, metal contacts, and device fabrication schemes is provided. Furthermore, various encapsulation techniques that have been proven effective in preventing the degradation of InSe and GaSe layers under ambient conditions are thoroughly discussed. Finally, this article presents an outlook on future research ventures with respect to ongoing developments and practical viability of these materials. image
22 February 2022 in ACS Applied Materials & Interfaces