| 摘要 |
PURPOSE:To enable response at high speed by forming an anode near a two-dimensional electron-gas forming interface in a light absorption layer and shaping a cathode in the position deeper than the anode in the light absorption layer in a semiconductor photoconductive photodetector having a modulation doping structure. CONSTITUTION:An electrode forming section is removed as deep as approximately 2000Angstrom in an InGaAs layer in a cathode 8 while an anode 7 is formed onto an n<+>-InAlAs layer 5, and the cathode 8 is shaped, and alloyed, thus forming an alloy layer 9 in the anode 7 up to a two-dimensinal electron gas 6 and an alloy layer 10 in the cathode 8 up to a section in the vicinity of approximately the center of the InGaAs layer 3. Consequently, electrons generated in the InGaAs layer 3 by optical pumping shape the two-dimensional electron gas 6 by the bending of a band, and are extracted to the anode 7 by a strong electric field. Holes generated near the surface shift to deep positions in the layer thickness direction by the bending of the band, but they move to the positions of the strong electric field because the cathode 8 is shaped up to approximately 2000Angstrom in depth in the InGaAs layer.
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