A CVD Diamond-Based Photodetector for the Visible and Near-IR Spectral Range

Abstract

A photodetector for the visible and near-IR spectral range has been created on the basis of a chemical- vapor-deposited diamond modulation-doped with boron. The detected electromagnetic radiation is absorbed in a thin Cr (7 nm)–Au (5.5 nm) bimetallic sublayer deposited on the surface of a modulationdoped diamond film comprising a highly doped (up to 5 × 10¹⁹ cm^–3) 3-nm-thick delta-layer, low-doped (~10¹⁷ cm^–3) 800-nm-thick sublayer, and highly doped (10²⁰ cm^–3) ~10-μm-thick sublayer with an ohmic Ti(50 nm)/Pt(15 nm)/Au(30 nm) contact. Holes generated in the bimetallic sublayer diffuse into diamond and are accelerated by an electric field in the low-doped sublayer to form a response photocurrent. The ampere/watt responsivity of the photodetector reaches 1 μA/W at a radiation wavelength of 445 nm and 0.18 μA/W at 1.06 μm.