Demonstration of a low power and high-speed graphene/silicon heterojunction near-infrared photodetector.

The structure and process of the graphene/Si heterojunction near-infrared photodetector were optimized to enhance the operating speed limit. The introduction of a well-designed structure improved the rise time from 12.6 μs to 115 ns, albeit at the expense of the responsivity, which decreased from 1.

High-performance near-infrared photodetectors based on gate-controlled graphene-germanium Schottky junction with split active junction.

The structure of a gate-controlled graphene/germanium hybrid photodetector was optimized by splitting the active region to achieve highly sensitive infrared detection capability. The strengthened internal electric field in the split active junctions enabled efficient collection of photocarriers, resulting in a responsivity of 2.02 A W and a specific detectivity of 5.

High Gain and Broadband Absorption Graphene Photodetector Decorated with BiTe Nanowires.

A graphene photodetector decorated with BiTe nanowires (NWs) with a high gain of up to 3 × 10 and wide bandwidth window (400-2200 nm) has been demonstrated. The photoconductive gain was improved by two orders of magnitude compared to the gain of a photodetector using a graphene/BiTe nanoplate junction. Additionally, the position of photocurrent generation was investigated at the graphene/BiTe NWs junction.

Gate-Controlled Graphene-Silicon Schottky Junction Photodetector.

Various photodetectors showing extremely high photoresponsivity have been frequently reported, but many of these photodetectors could not avoid the simultaneous amplification of dark current. A gate-controlled graphene-silicon Schottky junction photodetector that exhibits a high on/off photoswitching ratio (≈10 ), a very high photoresponsivity (≈70 A W ), and a low dark current in the order of µA cm in a wide wavelength range (395-850 nm) is demonstrated. The photoresponsivity is ≈100 times higher than that of existing commercial photodetectors, and 7000 times higher than that of graphene-field-effect transistor-based photodetectors, while the dark current is similar to or lower than that of commercial photodetectors.

Diagnostic assay of trace lead in an ex vivo tissue using a combination electrode.

A voltametric diagnosis of trace lead was performed using macro type combination sensors of fluorine-doped graphite pencil electrodes (FPE). Two pencils were used as the reference and auxiliary instead of expensive Ag/AgCl standards and Pt counters. Under optimized conditions, a square wave (SW) stripping working curve was attained at 10-70 mg/L and a micro range of 10-70 μg/L.