Impact of Nitrogen, Boron and Phosphorus Impurities on the Electronic Structure of Diamond Probed by X-ray Spectroscopies

Sneha Choudhury,Christian Schulz,Jean-Charles Arnault,Klaus Lieutenant,Marie-Amandine Pinault-Thaury,Tristan Petit,Ronny Golnak,Peter Knittel,Nicolas Tranchant,François Jomard

doi:10.3390/c7010028

Abstract

Doping diamond with boron, nitrogen or phosphorus enables a fine tuning of its electronic properties, which is particularly relevant for applications involving electron emission. However, the chemical nature of the doping sites and its correlation with electron emission properties remain to be clarified. In this work, we applied soft X-ray spectroscopy techniques to probe occupied and unoccupied electronic states in undoped, boron-, phosphorus- and nitrogen-containing single crystal diamonds. X-ray absorption, X-ray emission and X-ray photoemission spectroscopies, performed at the carbon K-edge, provide a full picture of new electronic states created by impurities in diamond. The different probing depths of fluorescence- and electron-based detection techniques enable a comparison between surface and bulk contributions.

Highlights

Diamond is a wide bandgap semiconductor with fascinating electronic properties that can be modulated by doping
The P-doped epilayer was grown in an ellipsoidal microwave plasma chemical vapor deposition (MPCVD) reactor using purified source gases (H2, CH4 ) and trimethylphosphine (diluted, P(CH3 )3 /H2 = 4500 ppm) at a gas pressure of 190 mbar [20]
The electronic structure of single crystal diamonds containing boron, nitrogen and phosphorus were compared by means of soft X-ray absorption, emission and photoemission spectroscopies

Summary

Introduction

Diamond is a wide bandgap semiconductor with fascinating electronic properties that can be modulated by doping. As a result, it is a promising versatile material for high power electronics, electron field emission, electrochemistry or quantum computing. In order to increase the diamond light absorption, nanostructuring [3,4], combination with dyes absorbing in the visible spectrum [5,6] and incorporation of metal nanoparticles to generate plasmonic effects [7] have been proposed. Incorporation of heteroatoms in the diamond matrix to add new absorption states is another approach that has been shown to enable visible light absorption [8]. Doping diamond with heteroatoms such as boron, nitrogen and phosphorus can tune the electron emission of the diamond as it has been thoroughly investigated over the last 25 years for electron field emission [9,10,11,12]

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Results

Conclusion