Preparation And Photosensitive Properties Of Mn,co,al-doped Sic Films

Due to the nature of SiC wide band gap, SiC prepared Ultraviolet detector can be used under extreme conditions, chemical and biological detection, flammable gas tail flame detection, ozone layer monitoring, short-wave communications and missile plume of smoke detection UV radiation fields, and applies to in the harsh environment of the photosensitive detector and sensor development. Currently for the photosensitive properties of SiC is also rarely reported, it is significance to carry out the UV photosensitive about study of SiC.SiC films doped with Manganese(Mn),Cobalt(Co)or Aluminum(Al)were prepared by the RF-magnetron sputtering and co-targets. The Crystal structure, surface morphology, doping concentration, chemical bonding state, carrier concentration and conductivity type, photoluminescence, ultraviolet absorption as well as photosensitivity properties of these films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Hall measurement system, fluorescence spectrometer, UV - visible light photometer and UV laser.The results show that:1) SiC films in the 2θ= 38.319°exist diffraction peaks ,and the structure is 6H-SiC (103) department of the hexagonal crystal. Mn, Co-doped SiC films crystal lattice occur leading to distortion, making 6H-SiC (103) diffraction peak intensity significantly decreased, Al-doped SiC films in the 2θ= 45.322°appeared diffraction peaks, indicating a 6H-SiC (105) crystal plane Peak.2)The spectra peaks of Mn, Co-doped SiC films were located at 423nm due to its increased Si vacancy concentration.It shows that the optical fluorescence peak at 423nm corresponds to the excitation light produced by electrons from the conduction band at the end of the Si vacancy shallow acceptor transitions between the levels of radiation which intensity depended on the Si vacancy concentration.3)Hall measurements found: un-doped SiC films carrier concentration is 7.121×10¹¹/cm², while 6at% Mn, Co, Al-doped SiC films carrier concentrations were 1.084×1016/cm²,2.793×10¹⁵/cm²,3.035×10¹²/cm². Un-doped SiC films, 4at% Mn-doped SiC films, Co-doped SiC films conductive type is n-type. More than 6at% Mn-doped SiC films whose conductivity type from n-type into p-type. Al-doped SiC films conductive type is p-type.4)Photosensitive testing found that Al, Co, Mn-doped SiC films enhanced significantly than un-doped SiC films in UV-absorption strength, and the Mn, Co-doped SiC films photosensitive sensitivity increased significantly with the doping concentration increased, whose response time were shorter than un-doped SiC films. Al, Co, Mn-doped SiC films were respectively sensitive on a wavelength range of 280nm 290nm, 290nm 310nm and 310nm 350nm. It is for the development of provides a material foundation in wide-band UV detection. The study also found that 6at% Mn-doped SiC films were1.5 times and 2 times than 6at% Co, Al-doped SiC films in photosensitive sensitivity. Mn, Co, Al-doped SiC films are superior than un-doped SiC films in photosensitive properties which are value of the films material in photocatalysis, solar cells, ultraviolet sensors and other field research.