Engineering the Interface Characteristics of Ultrananocrystalline Diamond Films Grown on Au-Coated Si Substrates

Abstract

Enhanced electron field emission (EFE) properties have been observed for ultrananocrystalline diamond (UNCD) films grown on Au-coated Si (UNCD/Au-Si) substrates. The EFE properties of UNCD/Au-Si could be turned on at a low field of 8.9 V/μm, attaining EFE current density of 4.5 mA/cm(2) at an applied field of 10.5 V/μm, which is superior to that of UNCD films grown on Si (UNCD/Si) substrates with the same chemical vapor deposition process. Moreover, a significant difference in current-voltage curves from scanning tunneling spectroscopic measurements at the grain and the grain boundary has been observed. From the variation of normalized conductance (dI/dV)/(I/V) versus V, bandgap of UNCD/Au-Si is measured to be 2.8 eV at the grain and nearly metallic at the grain boundary. Current imaging tunneling spectroscopy measurements show that the grain boundaries have higher electron field emission capacity than the grains. The diffusion of Au into the interface layer that results in the induction of graphite and converts the metal-to-Si interface from Schottky to Ohmic contact is believed to be the authentic factors, resulting in marvelous EFE properties of UNCD/Au-Si.

Gold nanoparticle–ultrananocrystalline diamond hybrid structured materials for high-performance optoelectronic device applications

“…3(a). 41,42 In the present study, due to the formation of Au-Si eutectic interlayer, the active Si species, which diffused easily through the interfacial layer, are in atomic form and are very active. 33,34 The inset in Fig.…”

High‐Performance Sensor Based on Thin‐Film Metallic Glass/Ultra‐nanocrystalline Diamond/ZnO Nanorod Heterostructures for Detection of Hydrogen Gas at Room Temperature

“…Thus, the existence of sp 2 at grain boundaries reduces the forbidden energy gap and increases the conductivity of the UNCD films. [15,16] The large surface area, excellent electrical properties, and effective surface passivation of the hybrid nanostructures in ZNRs/UNCD films make them an ideal structure for sensing applications.C omposite structures of ZNR and UNCD provide ah igh surface-to-volumer atio and al arge number of surfacet raps to facilitatet he sensing of hydrogen gas. UNCD films also help to increase the chargec arrier lifespan( referring to the electrons produced from the reaction of hydrogen gas and the adsorbed oxygen),w hich decreasest he carrier transit time.…”

Multienergy gold ion implantation for enhancing the field electron emission characteristics of heterogranular structured diamond films grown on Au-coated Si substrates

“…The process of Au and Cr deposition on Si and the pre-seeding process for the growth of diamond on these Au(Si) substrates are described in detail elsewhere. 15,16 The UNCD films were first deposited using microwave plasma enhanced chemical vapor deposition (MPECVD) system in Ar(99%)/CH 4 (1%) plasma under 1200 W and 120 Torr for 90 min. The plane view scanning electron microscopy (SEM; Jeol 6500) image shown in Fig.…”

“…2, which reveal the fascinating FEE properties of these films. The details of the FEE experiments are given elsewhere 15 and the FEE properties of these films were analyzed using the Fowler Nordheim (FN) theory. 29 The plots of ln(J/E 2 )-1/E (curve I, Fig.…”

“…Hence, the formation of Au(Si) eutectic layer eliminates the origin of the a-C phase in the vicinity of interface, which lowers the resistivity of the interface layer. 15,16 Seemingly, the SiC was formed due to the interaction of Si and C species, i.e., the Si species have diffused through the Au(Si) eutectic layer to react with the carbon promptly, forming SiC. The SiC can enhance the efficiency for the nucleation of diamond.…”