Germanium/perovskite heterostructure for high-performance and broadband photodetector from visible to infrared telecommunication band

A high-performance and broadband heterojunction photodetector has been successfully fabricated. The heterostructure device is based on a uniform and pinhole-free perovskite film constructed on top of a single-crystal germanium layer. The perovskite/germanium photodetector shows enhanced performance and a broad spectrum compared with the single-material-based device. The photon response properties are characterized in detail from the visible to near-infrared spectrum. At an optical fibre communication wavelength of 1550 nm, the heterojunction device exhibits the highest responsivity of 1.4 A/W. The performance is promoted because of an antireflection perovskite coating, the thickness of which is optimized to 150 nm at the telecommunication band. At a visible light wavelength of 680 nm, the device shows outstanding responsivity and detectivity of 228 A/W and 1.6 × 1010 Jones, respectively. These excellent properties arise from the photoconductive gain boost in the heterostructure device. The presented heterojunction photodetector provides a competitive approach for wide-spectrum photodetection from visible to optical communication areas. Based on the distinguished capacity of light detection and harvesting from the visible to near-infrared spectrum, the designed germanium/perovskite heterostructure configuration is believed to provide new building blocks for novel optoelectronic devices.Perovskite-germanium layers for broadband light detectionA device made from germanium and perovskite layers can detect light in the visible and near-infrared ranges, showing potential for use in a wide range of applications, including in optical communications and next-generation optoelectronics. This heterojunction photodetector fabricated by Chunlai Xue of the Chinese Academy of Sciences and colleagues overcomes problems in single-material photodetectors, which are unable to detect a broad range of light. Recent research into various combinations of semiconducting materials for heterojunction photodetectors has led to devices with poor sensitivity to light or that require a high working voltage. Adding a layer of methylammonium lead triiodide perovskite to a layer of germanium resulted in a highly sensitive photodetector at the optical fibre communication wavelength of 1550 nm (near-infrared range) and the visible light wavelength of 680 nm.