Preparation And Properties Of The A-C:H Films And The A-C:H:Fe Films

Hydrogenated amorphous carbon(a-C:H)films have widespread applications such as in the fields of protective,biomedical and optical materials because of their favorable mechanical,electrical and optical properties.The a-C:H films are also used as coating on the shell surface in the inertial confinement fusion(ICF).Alloying a-C:H films with transition metal Fe have common strategies to reduce the high residual compressive stress of the a-C:H films and to improve the poor adhesion between the a-C:H films coating and substrates.In addition,Fe possesses actions to reduce above-thermal electrons to heat fusion fuel in advance and bremsstrahlung effect between electrons and other particles.Finally,photoelectric properties of the a-C:H films is enriched and improved for Fe as a deep level.In this paper,Fe-doped a-C:H(a-C:H:Fe)films were deposited,and influence of Fe-doped on deposition rate, composition,surface topography,structure,thermal stability,optical properties and electron field emission(FE)characteristics of the a-C:H films were studied.In this paper,the a-C:H:Fe films were successfully deposited by metal organic plasma enhanced chemical vapor deposition(MOPECVD).Composition,surface topography and microstructure of the a-C:H films and the a-C:H:Fe films were studied.Comparison between the measurements on the two types films demonstrates that both films are smooth,plane and uniform,but the a-C:H:Fe films are more compact and grain of their surface are smaller,and that the a-C:H:Fe films contain more six-fold rings,C=C bands and sp~2 clusters than that of the a-C:H films.In this paper,deposition rate and thermal stability of the a-C:H films and the a-C:H:Fe films were compared,and optical properties and electron field emission characteristics of the two types films were studied.Comparison between the measurements on the two types films demonstrates that the a-C:H:Fe films are at a higher deposition rate than the a-C:H films for ferrocene as a catalyst,and that the a-C:H:Fe films are more easily carbonized in process of heating Ar ambient or etching air ambient than the a-C:H films.The Tauc optical gaps of the a-C:H:Fe and the a-C:H films are 2.97 eV and 2.67 eV,respectively.PL center is shifted from 2.35 eV in the a-C:H films to 1.95 eV in the a-C:H:Fe films,and PL intensity is greatly enhanced in the a-C:H:Fe films.In addition,both ultrathin a-C:H and a-C:H:Fe films are responsible for F-N model,and the work function of the ultrathin a-C:H:Fe films is higher than the ultrathin a-C:H films.The changes of these properties are linked to the conclusions such as more compact surface,more six-fold rings,C=C bands and sp~2 clusters in the a-C:H:Fe films than that in the a-C:H films.