NOVELTY - A diamond-like carbon electronic device (26), comprises a diamond-like carbon cathode (34) including a conductive diamond-like carbon material having an sp3 bonded carbon content of 30-90 atom%, a hydrogen content of 0-30 atom%, and an sp2 bonded carbon content of 10-70 atom%; a charge carrier separation layer (28) adjacent the diamond-like carbon cathode; and an anode (36) adjacent the charge carrier separation layer opposite the diamond-like carbon cathode.    USE - As a diamond-like carbon electronic device e.g. solar cell, a fuel cell (claimed), LEDs, and thermoelectric conversion devices.    ADVANTAGE - The conductive diamond-like carbon material enhances performances of the electronic devices. The conductive diamond-like carbon material is chemically inert, and has radiation damage resistance. Thus, the electronic device is simple to manufacture. The wafer or semiconductor surface can be etched to roughen the surface and/or can include features such as pyramidal depressions or extensions which increase surface areas of the device. The features can be varied in size and geometry based on balancing performances, cost and material limitations. The etching of pyramidal extensions or depressions can be particularly useful in enhancing performance. The diamond-like carbon electronic devices allow for a significant reduction in the thickness of the charge carrier separation layer because of elimination or reduction of any buried metal grid electrodes. The diamond-like carbon cathode can allow the semiconductor layer to be substantially planar. The devices can be free of 5 trenches and/or metal grid materials which are present in conventional silicon solar cells. The use of conductive diamond-like carbon material can also prevent the thinner semiconductor layers from warping. The use of amorphous or diamond-like carbon material reduces thermal mismatch between layers of the device. The silicon, silicon carbide and diamond-like carbon have thermal expansion coefficient of around 4 parts per million (ppm)/degrees C, which dramatically reduces the thermal mismatch stress during and after processing. This affect also reduces de-lamination as substantially all of the layers of the device can have substantially similar thermal expansion properties such that during thermal cycling and extended use, interfaces between layers retain interfacial strength. The solar cells can have conversion efficiencies of 18-25%, although further improved performances can be obtained by judicious optimization and choice of materials. The graded and/or multi-junction embodiments can potentially realize efficiencies of up to 10%, over conventional silicon solar cell efficiencies which are currently 15-18%. Because aluminum covers the entire back side of the silicon layer, the conductive diamond-like carbon does not distort the thin silicon layer. The silicon or semiconductor layer is not processed at a conventional high temperature, e.g. around 800degrees C. The diamond-like carbon can form an excellent ohmic contact with silicon such that additional coating of silver does not require a high temperature sintering of silver, where only low temperature sintering is needed, e.g. less than about 300degrees C. The diamond-like carbon electronic devices can be heat treated in vacuum furnace, and heat treatment can improve the thermal and electrical properties across boundaries interfacial boundaries and reduce material defects.    DETAILED DESCRIPTION - A diamond-like carbon electronic device (26), comprises a diamond-like carbon cathode (34) including a conductive diamond-like carbon material having an sp3 bonded carbon content of 30-90 atom%, a hydrogen content of 0-30 atom%, and an sp2 bonded carbon content of 10-70 atom%; a charge carrier separation layer (28) adjacent the diamond-like carbon cathode; and an anode (36) adjacent the charge carrier separation layer opposite the diamond-like carbon cathode. The conductive diamond-like carbon material further includes a dopant. The sp2 bonded carbon content is sufficient to provide the conductive diamond-like carbon material with a visible light transmissivity of greater than 0.70. The sp2 bonded carbon content is 35-60 atom%; and hydrogen content is 15-25 atom%. The diamond-like carbon cathode and anode further include a conductive additive selected from conductive metal particles, carbon nanotubes, graphite, and/or conductive nanoparticles. The charge carrier separation layer is a semiconductor layer. The charge carrier separation layer comprises at least a portion of a p-n or p-i-n junction. The charge carrier separation layer further comprises multiple p-n or p-i-n junctions to form a multi-junction solar cell; an n-doped region and a p-doped region; or a p-doped region and the diamond-like carbon cathode includes an n-doped region. The charge carrier separation layer is planar. The cathode is a single layer and is configured as a passivation layer and an anti-reflection layer. The charge separation carrier layer comprises a crystalline material. The diamond-like carbon electronic cathode consists essentially of the conductive diamond-like carbon. The charge carrier separation layer is compositionally graded; and has a thickness of 10-300 mu m. An INDEPENDENT CLAIM is included for forming the diamond-like carbon electronic device, involving preparing a charge carrier separation layer; forming an anode that is coupled adjacent the charge carrier separation layer; forming a diamond-like carbon cathode coupled to the charge carrier separation layer opposite the anode, where cathode includes a diamond-like carbon material having a conductivity of 0-80 mu Omega at 20degrees C, and a visible light transmissivity of 0.5-1, where conductivity and visible light transmissivity is a function of sp2 and sp3 bonded carbon content, hydrogen content, and optional conductive additives.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-sectional view of the compositionally graded diamond-like carbon composite solar cell.    diamond-like carbon electronic device (26)    charge carrier separation layer (28)    n-doped area (30)    p-doped area (32)    diamond-like carbon cathode (34)    anode. (36)