@article{LI2026, 
author = {Weijian LI and Ning CHEN and Hongwei WANG and Hao WANG and Shixiu ZHAO and Yilong PAN},
title = {Nitrogen Aggregation Induced by High-Pressure High-Temperature Pretreatment and Its Effect on the Apparent Charge-State Ratio of NV Centers in Diamond},
year = {2026},
journal = {Chinese Journal of High Pressure Physics},
volume = {40},
number = {9},
keywords = {diamond, nitrogen-vacancy (NV) center, electron irradiation, vacuum annealing, high-pressure high-temperature},
url = {https://www.sciopen.com/article/10.11858/gywlxb.20261106},
doi = {10.11858/gywlxb.20261106},
abstract = {Formation of nitrogen-vacancy (NV) centers and their apparent charge-state response in high-pressure high-temperature (HPHT) type-Ⅰb diamond were investigated. Effects of the initial substitutional nitrogen content (C-center nitrogen), electron irradiation, vacuum annealing, and HPHT pretreatment on the photoluminescence (PL) behavior of NV centers were compared. Two groups of HPHT diamond single crystals with different C-center nitrogen contents were subjected to electron irradiation, vacuum annealing (600−1000 ℃), and HPHT pretreatment (5 GPa, 1100−1900 ℃). Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and photoluminescence spectroscopy were employed to analyze nitrogen aggregation, lattice state, and NV-related photoluminescence responses. The results show that high-nitrogen samples exhibit more pronounced NV-related emission, whereas irradiation-induced vacancies in the low-nitrogen samples tend to remain as GR1 centers. As the vacuum annealing temperature increases, the overall emission intensities of NV0 and NV− increase, while the apparent photoluminescence response of NV− relative to NV0 generally decreases. HPHT pretreatment does not directly generate a large number of NV centers but promotes nitrogen aggregation and modifies the apparent NV−/NV0 charge-state ratio during subsequent irradiation and annealing. These results indicate that HPHT pretreatment can serve as a preceding processing parameter for regulating the initial defect state before irradiation and the subsequent apparent charge-state ratio of NV centers.}
}