Electron emission from conduction band of heavily phosphorus doped diamond negative electron affinity surface. (24th December 2015)

• Record Type: Journal Article
• Authors: Yamada, Takatoshi; Masuzawa, Tomoaki; Mimura, Hidenori; Okano, Ken
• Is Part Of: Journal of physics. Volume 49:Number 4(2016)
• Publication Date: 2015-12-24
• Subjects: diamonds -- negative electron affinity -- field emission -- ultraviolet photoelectron spectroscopy; Physics -- Periodicals; 530
• DOI: 10.1088/0022-3727/49/4/045102
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: Hydrogen (H)-terminated surfaces of diamond have attracted significant attention due to their negative electron affinity (NEA), suggesting high-efficiency electron emitters. Combined with n-type doping technique using phosphorus (P) as donors, the unique NEA surface makes diamond a promising candidate for vacuum cold-cathode applications. However, high-electric fields are needed for the electron emission from the n-type doped diamond with NEA. Here we have clarified the electron emission mechanism of field emission from P-doped diamond having NEA utilizing combined ultraviolet photoelectron spectroscopy/field emission spectroscopy (UPS/FES). An UP spectrum has confirmed the NEA of H-terminated (1 1 1) surface of P-doped diamond. Despite the NEA, electron emission occurs only when electric field at the surface exceeds 4.2 × 10 6 V cm −1 . Further analysis by UPS/FES has revealed that the emitted energy level is shifted, indicating that the electron emission mechanism of n-type diamond having NEA surface does not follow a standard field emission theory, but is dominated by potential barrier formed within the diamond due to upward band bending. The reduction of internal barrier is the key to achieve high-efficiency electron emitters using P-doped diamond with NEA, of which application ranges from high-resolution electron spectroscopy to novel vacuum nanoelectronics devices.