We report results of quantum efficiency (QE) measurements carried out on a 150 nm thick nitrogen-incorporated ultrananocrystalline diamond terminated with hydrogen; abbreviated as (N)UNCD:H. (N)UNCD:H demonstrated a QE of ∼10−3 (∼0.1%) at 254 nm. Moreover, (N)UNCD:H was sensitive in visible light with a QE of ∼5×10−8 at 405 nm and ∼5×10−9 at 436 nm. After growth and prior to QE measurements, samples were exposed to air for about 2 hours for transfer and loading. Such design takes advantage of a key combination: 1) H-termination inducing negative electron affinity (NEA) on the (N)UNCD and stabilizies its surface against air exposure; and 2) N-incorporation inducing n-type conductivity in intrinsically insulating UNCD.
@article{arxiv.1407.5113,
title = {High Quantum Efficiency Ultrananocrystalline Diamond Photocathode: Negative Electron Affinity Meets $n$-doping},
author = {K. J. Pérez Quintero and S. Antipov and A. V. Sumant and C. Jing and A. D. Kanareykin and S. V. Baryshev},
journal= {arXiv preprint arXiv:1407.5113},
year = {2015}
}