Abstract: A photodetector includes a substrate, a graphene layer disposed on the substrate, a first electrode disposed on the graphene layer, and a second electrode disposed on the graphene layer, where the first and second electrodes are spaced apart from each other, and where each of the first and second electrodes comprises a complex transparent electrode. The complex transparent electrode of the first electrode may have a different composition from the complex transparent electrode of the second electrode.

Abstract: A photodetector includes a substrate, a graphene layer disposed on the substrate, a first electrode disposed on the graphene layer, and a second electrode disposed on the graphene layer, where the first and second electrodes are spaced apart from each other, and where each of the first and second electrodes comprises a complex transparent electrode. The complex transparent electrode of the first electrode may have a different composition from the complex transparent electrode of the second electrode.

Abstract: The present invention provides reduction of injury to the human body by effectively reducing short-distance electromagnetic waves without any influence on long-distance electromagnetic waves which act upon a telephone communication amongst electromagnetic waves radiated from antenna of mobile communication terminals. An electromagnetic wave absorber, absorbing short-distance electromagnetic wave, is installed at the exterior of a metal rod fixed to a helical antenna, an upper portion of the electromagnetic wave absorber is formed having a big diameter, a lower portion is formed having a small diameter, and a through bore is formed at the central portion, said metal rod being inserted at through bore or is in its entirety formed as a cylinder, and formation of a through bore at the central portion leads said helical antenna to be inserted at through bore or leads electromagnetic wave absorber to be inserted and integrally formed thereon.

Abstract: A mobile telecommunication apparatus comprises a front cover defining a display opening, wherein the front cover includes a front and rear surface; and at least one electromagnetic energy absorbing ferrite disposed near the rear surface and display opening of the front cover, wherein the ferrite comprises about 80 to 85 wt. % of Fe2O3, about 9 to 15 wt. % of MnO2, about 8 to 10 wt. % of ZnO and 1 to 3 wt. % of SiO2. Preferably, four ferrites are attached to the rear surface of the front cover near each corner of the display opening. Each ferrite has a weight of about 0.1 to 0.3 grams, and preferably, about 0.2 grams.

Abstract: A ceramic composition for absorbing electromagnetic waves and a method for manufacturing the same are disclosed. The composition comprises a raw powder comprising by weight between about 35% to 65% Fe.sub.2 O.sub.3, between about 1% to 5% Al.sub.2 O.sub.3, between about 0.5% to 1.5% Zn, between about 0.5% to 1.0% Cr, between about 3% to 10% Cu, between about 3% to 8% Mn, and between about 1% to 4% Co, and a mixture around the raw powder comprising by weight between 30% to 40% water, between 1.5% to 2.0% a dispersing, and between 1.5% to 2% a plasticizer. The method comprises the steps of grinding the powder, spray drying the grounded powder, forming the sprayed powder into a predetermined shape, calcinating and sintering the shape in a furnace, and cooling the sintered shape gradually. The ceramic composition absorbs the electromagnetic waves generated from electric devices such as cellular phones, beepers, computers, cordless telephones, etc.