Surface terminations of diamond play an important role in determining the electric properties of diamond-based electronic devices.We report an ultraviolet/ozone(UV/ozone)treatment process on hydrogen-terminated single...Surface terminations of diamond play an important role in determining the electric properties of diamond-based electronic devices.We report an ultraviolet/ozone(UV/ozone)treatment process on hydrogen-terminated single crystal diamond(H-diamond)to modulate the carrier behavior related to varying oxygen adsorption on surfaces.By UV/ozone treatments,the induced oxygen radicals are chemically adsorbed on the H-terminated diamond and replace the original adsorbed H,which is analyzed by x-ray photoelectron spectroscopy.The concentration of oxygen adsorbed on surface increases from^3%to^8%with increasing the ozone treatment time from 20 s to 600 s.It is further confirmed by examining the wettability properties of the varying diamond surfaces,where the hydrophobic for H-termination transfers to hydrophilic for partly O-termination.Hall effect measurements show that the resistance(hole mobility)of the UV/ozone-treated H-diamond continuously increases(decrease)by two orders of magnitude with increasing UV/ozone treatment time from 20 s to 600 s.The results reveal that UV/ozone treatment becomes an efficient method to modulate the surface electrical properties of H-diamonds for further investigating the oxygenation effect on two-dimensional hole gas based diamond devices applied in some extreme environments.展开更多
The contact angle and surface energy values of diamond are systemically investigated in terms of surface treatments(hydrogen-and oxygen-terminations), structure feature(single crystal diamonds and polycrystalline diam...The contact angle and surface energy values of diamond are systemically investigated in terms of surface treatments(hydrogen-and oxygen-terminations), structure feature(single crystal diamonds and polycrystalline diamond films), crystal orientation((100),(111) and mixed(100)/(111) orientations), different fluids(probes of polar deionized water and nonpolar di-iodomethane). It is found that the hydrophobic/hydrophilic characteristic and surface energy values of diamond are mainly determined by the surface hydrogen/oxygen termination, and less related to the structural features and crystal orientation. Based on the contact angle values with polar water and nonpolar di-iodomethane, the surface energies of diamond are estimated to be about 43 m J/m^2 for hydrogen-termination and about 60 m J/m^2 for oxygen-termination. Furthermore, the varying surface roughness of diamond and fluids with different polarities examined determine the variation of contact angles as well as the surface energy values. These results would be helpful for a more detailed understanding of the surface properties of diamond films for further applications in a broad number of fields, such as optical and microwave windows,biosensors, and optoelectronic devices, etc.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos.51672102 and 51972135。
文摘Surface terminations of diamond play an important role in determining the electric properties of diamond-based electronic devices.We report an ultraviolet/ozone(UV/ozone)treatment process on hydrogen-terminated single crystal diamond(H-diamond)to modulate the carrier behavior related to varying oxygen adsorption on surfaces.By UV/ozone treatments,the induced oxygen radicals are chemically adsorbed on the H-terminated diamond and replace the original adsorbed H,which is analyzed by x-ray photoelectron spectroscopy.The concentration of oxygen adsorbed on surface increases from^3%to^8%with increasing the ozone treatment time from 20 s to 600 s.It is further confirmed by examining the wettability properties of the varying diamond surfaces,where the hydrophobic for H-termination transfers to hydrophilic for partly O-termination.Hall effect measurements show that the resistance(hole mobility)of the UV/ozone-treated H-diamond continuously increases(decrease)by two orders of magnitude with increasing UV/ozone treatment time from 20 s to 600 s.The results reveal that UV/ozone treatment becomes an efficient method to modulate the surface electrical properties of H-diamonds for further investigating the oxygenation effect on two-dimensional hole gas based diamond devices applied in some extreme environments.
基金Supported by the National Natural Science Foundation of China under Grant Nos.51672102 and 51972135.
文摘The contact angle and surface energy values of diamond are systemically investigated in terms of surface treatments(hydrogen-and oxygen-terminations), structure feature(single crystal diamonds and polycrystalline diamond films), crystal orientation((100),(111) and mixed(100)/(111) orientations), different fluids(probes of polar deionized water and nonpolar di-iodomethane). It is found that the hydrophobic/hydrophilic characteristic and surface energy values of diamond are mainly determined by the surface hydrogen/oxygen termination, and less related to the structural features and crystal orientation. Based on the contact angle values with polar water and nonpolar di-iodomethane, the surface energies of diamond are estimated to be about 43 m J/m^2 for hydrogen-termination and about 60 m J/m^2 for oxygen-termination. Furthermore, the varying surface roughness of diamond and fluids with different polarities examined determine the variation of contact angles as well as the surface energy values. These results would be helpful for a more detailed understanding of the surface properties of diamond films for further applications in a broad number of fields, such as optical and microwave windows,biosensors, and optoelectronic devices, etc.
