Characterization of diamond ultraviolet detectors fabricated with high-quality single-crystalline chemical vapor deposition films

We have fabricated high-performance ultraviolet (UV) detectors with high-quality undoped and B-doped homoepitaxial diamond layers which were sequentially grown on a high-pressure/high-temperature-synthesized (HPHT) type-Ib (100) substrate by means of a high-power microwave-plasma chemical vapor deposition method. The detector performance measured had large quantum efficiencies due to an effective built-in current amplification function, fast temporal responses, and high UV/visible sensing ratios although the HPHT substrate used had considerable amounts of various defects inducing visible light absorptions and slow detector responses. The usefulness of the bilayer detector structure employed is discussed.