Interaction between alkali metals and diamond: Etching and charge states of NV centers

Single crystal diamond particles were heated with liquid phase alkali metals (Li, Na, K) in an argon atmosphere. It was found that Li reacts with the diamond above 600 degrees C, Na makes the surface rougher on a nm scale at 800 degrees C, and K did not change the surface morphology. The etching speed by the reaction with Li is the fastest on the (001) surface. Photoluminescence of the NV- (negatively charged nitrogen vacancy) center decreased only after the annealing with K. DFT calculations explained the strong chemical interaction between Li and the diamond (001) surfaces, and upward band bending at the interfaces with Na and K. The behavior of the NV-center photoluminescence is consistent with the extent of band bending. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Different alkali metals (Li, Na, K) react with single crystal diamond particles at different temperatures and have varying effects on the surface morphology. Li reacts the fastest, Na makes the surface rougher, and K has minimal impact. The photoluminescence of the NV-center is only affected after annealing with K, in accordance with band bending behavior.