Impurity-mediated near-infrared (NIR) photoresponse in silicon is of great interest for photovoltaics and photodetectors. In this paper, we have fabricated a series of n+/p photodetectors with hyperdoped silicon prepared by ion-implantation and femtosecond pulsed laser. These devices showed a remarkable enhancement on absorption and photoresponse at NIR wavelengths. The device fabricated with implantation dose of 1014 ions/cm2 has exhibited the best performance. The proposed method offers an approach to fabricate low-cost broadband silicon-based photodetectors.
In this paper, we have designed and experimentally demonstrated a broadband absorber in the mid-infrared region based on the impedance matching method. The absorber is made of planar multilayered dielectric and metallic films without involving lithography in fabrication. Our measurements reveal high absorption over 85% in the wavelength range of 2.2-6.2 μm. This wideband absorption is shown to be independent of the polarization and can be maintained over a range of incident angles up to 45°. The resultant absorber has potential applications for thermal shielding, camouflaging, sensing, etc.
As an emerging optoelectronic material, graphene's universal absorption of about 2.3% over a broad frequency range from infrared to visible, as determined by its interband transition, presents both a new opportunity and a limitation. Here we report on a multifold enhancement of the absorption using a simple strategy, often referred to as the Salisbury screen. It consists of a graphene sheet on top of a SiO2 dielectric layer backed with a copper metallic reflector. For a monolayer graphene, peak absorptions of 9% at near normal incidence and 40% at near grazing angle are experimentally demonstrated in the near-infrared region, in good agreement with calculations using transfer matrix method. The resultant absorption enhancement suggests a great potential for graphene to be used in infrared optoelectronic components.
A graphene-Si junction is an attractive system as it is both CMOS-compatible and representative of very interesting van der Waals (vdW) heterostructures. In this paper, the full spectral photoresponse of the graphene-Si heterojunction is investigated in the photovoltaic mode by using Fourier transform infrared photocurrent spectroscopy. Two photoresponse bands at 980 nm and 1550 nm are measured, which are attributed to the photocarrier generations in Si and in the graphene-Si vdW junction, respectively. Peak detectivities of the Si and the vdW junction photoresponses are measured to be 1.3 × 109 cm Hz1/2/W and 1.3 × 108 cm Hz1/2/W, respectively. The band diagram of the heterojunction suggests an indirect spatial transfer process from graphene to silicon. The results are indicative of great potential of the graphene-Si vdW junction for photodetection in the infrared region.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.