▎ 摘　　要

NOVELTY - The photodetector has a housing that is configured along a carrier (20) arranged downhole within a borehole (26). A graphene tunneling photodetector is located within the housing and configured to perform a downhole operation. A chamber has a downhole fluid sample contained. A light source illuminates the downhole fluid sample within chamber. A graphene tunneling sensor portion in optical communication with the downhole fluid sample which senses light that impinges the downhole fluid sample to estimate a property of downhole fluid sample. USE - Photodetector for downhole tool such as sampling tool for performing downhole operation, of drilling system. Uses include but are not limited to acoustic tools, nuclear tools, nuclear magnetic resonance tools and formation testing and sampling tool. ADVANTAGE - The downhole photodetectors and spectrometers are employed with graphene tunneling photodetectors, so as to enable spectral measurements from which estimation of physical and chemical properties of a downhole fluid. The drilling system utilizes a drill pipe so as to convey BHA into the borehole, so that weight on bit is controlled from surface by controlling operation of drawworks. The graphene tunneling spectrometer enables a downhole sampling tool to perform spectroscopy downhole during and prior to sampling, after sampling and at surface. The graphene tunneling sensor portion is employed within a photodetector to enable detection of multiple and various wavelengths of light without performance degradation with increasing temperature. The high-temperature photodetectors and other types of downhole sensors are provided with excellent light sensitivity over a broad spectrum of light wavelengths for use in downhole fluid analyzers and with fiber optic sensors. The optical window is positioned between the chamber and graphene tunneling sensor portion to enable light to pass from chamber to the graphene tunneling sensor portion. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for performing a downhole operation using a photodetector. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a drilling system. Carrier (20) Borehole (26) Return line (35) Mud motor (55) Lower kick-off subassembly (62)