NOVELTY - N-type diamond semiconductor monocrystal contains regularly arranged to substitute carbon atoms which are nitrogen atom, lithium atom, and beryllium atom in which total amount of nitrogen-lithium atoms, nitrogen-beryllium atoms, and lithium-nitrogen-beryllium atoms is 100-10000 ppm, size of N-type diamond semiconductor single crystal is 0.3-10 mm, and crystal shape is regular hexahedron, regular octahedron, or 6-octahedron.    USE - An N-type diamond semiconductor monocrystal for solar energy battery and LED light source.    ADVANTAGE - Product has good electrical conductivity, high conversion efficiency, and long service life, and is environment-friendly.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of N-type diamond semiconductor monocrystal which involves mixing pure graphite powder:metal catalyst:lithium nitride:beryllium nitride with mass ratio of 0.4-1:0.6-1:0.01-0.05:0.01-0.05, pressurizing mixture to 100-300 MPa through cold isostatic pressing treatment to obtain pressed material, relieving for 2-10 minutes, crushing pressed material into 2-20 mesh particles, pressing particles in mold into cylindrical synthesis column, subjecting cylinder into vacuum sintering furnace and sintering at 1000-1200degrees C for 2-18 hours to obtain sintered composite cylinder and loading into synthetic block, subjecting block into cubic press at 6-8 GPa, performing magnetic field orientation to block at 1100-2000degreesC for 10-2800 minutes, relieving block and removing synthetic column, crushing synthetic column, putting material into electrolytic cell and perform electrolysis to obtain metal column which is synthesized electrolytic deposition on cathode plate and remaining material is diamond, graphite, and residual unconverted slurry-like mixture consisting of metal, and shaking to separate slurry-like mixture.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of an N-type diamond semiconductor monocrystal microstructure.