The Generation And Quench Of Phosphorescence On High-temperature-high-pressure Synthetic Type Ⅱ Diamond-the Role Of Boron,Nitreogen And The Vacancy

Under the excitation of ultraviolet light(UV)in proper wavelength,Hightemperature-high-pressure(HPHT)synthetic type II diamonds would emit a greenish blue phohsphorescence centered in 485 nm and an orangy red phsohphorescence near 590 nm.The 485 nm greenish blue emission in diamonds in Diamond ViewTM(or other counterpart apparatus)helps us to screen HPHT synthetic diamonds quickly.Recently,there are increasingly cases,from the institutions and laboratories,that electron irradiation can quench the phsophorescece and that make the sapration process become more inefficient.In sipte of the significance of the greenish blue phosphorescence on diamond separation and the emergency of the new techlogocial changenllge,today people have limited backgournd knowledge on its mechanism.According to Donor-acceptor-pair recombination theory(DARP),this phenomenon was ascribed to the charge compensation between the donor and acceptor in diamond.For now,this hot issue focus on identifying the donor and acceptor and explaining the reason for quench by electron irradiaiton.Based on the situation of industry,our project is identifing the donor of DAPR,building the connection between defects and luminescence,and confirming the role of vacancy in the process of quenching.Using the photoluminescence spectroscopy(PL),fourier transform infrared spectroscopy(FTIR)and ecletron paramagnetic resonance spectroscopy(EPR),we collected and analysised the perporiteis on phsophoresncece and the defects from 28 pieces of HPHT synthetic diamonds.The result showed that these diamonds can be divided into two catagories.The first one exhibit greenish blue phoshphoresne only,but the second one has orangy red phosphorescence additionly.For the greenish blue phosphorescence,we discovered that the signal of netural isolated nitreogen(NS0)and boron(BS0)in EPR and FTIR would arise or grow during the excitation.The amplitude of these increaments have a positive correlation.Also,the intensity of the luminescence correlated positively to increaments of both defect at the same time.All these evidences confirm that nitrogen and the boron is the donor and acceptor for phosphorescence.We also used 1.2 and 10.0 Me V electron to irradiate our diamond in various dose and quenched the luminensece successfully in different degree.The 1.2 Me V electron irradiation has a faint decline on the intensity of phsophorescnece and the derecement on defect concentration.But the 10.0 Me V,16000 k Gy irradiaton quenched greenish blue phosphoresnce completely.That mathes the assumpsion of the DAPR theory,the excessive netrual singl vacancy can interact with BS0 and NS0 respcetively,and distory the greenish blue phsophoresnce.For orangy red phsophorescnece,we discovered that the orangy red one is only associated with BS0,insited of the NS0.Meanwhile,the existence of the orangy red phsophorescnece seemed to compete BS0 with greenish blue phosphoresncece and that may change the lifetime of greenish blue phosphoresncece.Following the analysis on the perporties of phosphoresnce and the defect,we idenfied that nitrogen and boron are donor and acceptor experimentally.Also,we confirm that vancy can quench the phosphorescence by distrupting the DAPR.In addition,we studed the properties of the orangy phsophoresnce and give some prilimenary guess.