"Surface Transfer Doping of Diamond and Ultrananocrystalline Diamond" |
| TYPE | RBNI Seminar |
| Speaker: | Mr. Moshe Tordjman |
| Affiliation: | RBNI/Physics |
| Date: | 27.11.2013 |
| Time: | 12:30 - 13:30 |
| Location: | |
| Remark: | Ph.D Studnet of Prof. Rafi Kalish and Dr. Cecile Saguy |
| Abstract: | Doping of diamond has drawn much attention in the last decades. When achieved, n- and ptype diamonds can serve as superior building blocks for electronic devices benefiting of diamond's extreme physical properties. Beside bulk doping of diamond, which has shown low efficiency in term of activation energy, a new surface doping concept has been developed in the last 10 years - the 'Surface Transfer Doping'. Surface transfer doping takes advantage of a negative electron affinity of the diamond surface when hydrogen terminated. Furthermore, when exposed to humid air, a high surface ptype conductive layer (a few nanometers thick) isformed thanks to the transfer of electron carriers from diamond valence band maximum to molecules' lower electrochemical potential. Thin layers of Ultra Nano Crystalline Diamond (UNCD), composed of nano-sized diamond crystallites (5-15nm) embedded in amorphous carbon (ta-C) were recently grown by CVD methods. These exhibit many of the superior properties of diamond. In our research, we have studies two aspects of diamond surface transfer doping: 1. The surface transfer doping effects of UNCD. This complex, combined with surface transfer doping treatments, has striking electron field emission phenomenon in which a switch-on and a reversible hysteresis ofthe emitted current occurs. These new phenomena have been explained by us to be due to a double-barrier resonant-tunneling of electrons through the quantumwells composed by a ta-C/Nano Diamond/Adsorbent/Vacuum heterostructure. 2. The use of a new transfer doping material, Molybdenum Trioxide (MoO3), as a transfer doping acceptor of H-terminated diamond replacing existing non-stable H2O molecules. We show that MoO3has superior surface transfer doping properties - as far as electrical conductivity and thermal stability are concerned. |