Photoelectron spectroscopy of boron-doped homoepitaxial diamond (100) surfaces with several terminations and related Schottky barriers

Abstract

The energy band diagram of boron-doped homoepitaxial C(100) diamond surfaces with different terminations are deduced from band-bending, electron affinity and work function data measured by ultraviolet photoelectron spectroscopy (UPS). Moreover, the electronic properties of the metallic interfaces fabricated by the deposit of one or several monolayers (ML) of erbium on these surfaces are investigated by UPS, electrical and photoelectrical measurements. The Schottky barrier properties are clearly related to the electronic properties of the various surfaces. Microwave plasma (hydrogen or oxygen) and annealing in ultra-high vacuum are used to obtain diamond surfaces either terminated by hydrogen (2×1), oxygen (1×1) or a free surface (2×1). After the deposition of 1 ML of Er, UPS shows that the highest Schottky barrier height is measured for the hydrogen-free surface (1.8 eV). The I–V characteristics of the Er contact to the free surface show good rectification up to 500 °C. On the contrary, the contact is ohmic on the hydrogenated surface.