Growth And Characterization Of Gallium Nitride Film On CNT-TCFs/quartz At Low Temperature

Gallium nitride?GaN?is the third generation semiconductor materials and it has shown tremendous potential in optoelectronic and electronic devices due to its wide direct-band gap,high electron mobility,high breakdown filed and chemical stability properties.It can be used for high-temperature,high-power and high-frequency devices.Substrate selection is very important for GaN crystal growth.If chose homogeneous substrate to grow GaN film,the cost will be high and it will be difficult to prepare large area GaN film.So in order to prepare high quality GaN many efforts need to spend to find other suitable substrate.High quality GaN have been prepared on crystalline such as silicon?Si?,silicon carbide?SiC?and sapphire?Al2O3?.GaN grown on silicon has been used in the commercial field in the past few years due to its low price and technology support.Some researchers studied the growth of GaN on substrates such as grapheme,hexagonal boron nitride?h-BN?,and molybdenum disulfide?MoS2?and got high quality GaN with low defects.Since the discovery of carbon nanotubes?CNTs?in 1991,they have been widely studied due to their unique structure and excellent optical and electrical properties.Carbon nanotube films include horizontal array films,vertical array films and transparent conductive films.Many researchers have prepared GaN on CNT array films,but have not studied the preparation of GaN on carbon nanotube transparent conductive films?CNT-TCFs?.CNT-TCFs are regared the best substitutes for ITO due to its excellent electrical and mechanical properties.In this paper,electron cyclotron resonance plasma enhanced metal organic chemical vapor deposition?ECR-PEMOCVD?equipment was used to prepare GaN films on CNT-TCFs/quartz at low temperature.The CNT-TCFs were prepared on quartz by sol-gel method and then depositing GaN film on CNT-TCFs/quartz substrate which was placed in the ECR-PEMOCVD coating chamber.The ECR-PEMOCVD equipped with microwave plasma source can deposite GaN film at low temperature.In this paper,five groups of CNT-TCFs samples were prepared by changing the ratio of CNTs:SDBS:H₂O.The transmittance and resistance of the five samples can be obtained by transmission spectrum and I-V curves.Resistance-transmission?R-T?scatter diagram shows that sample 2 is the best over the five samples.Sample 2 was obersved by scanning electron microscope?SEM?,CNTs can be found in CNT-TCFs disorderded arrangemen,connected to each other,local clusters CNTs convex shape.CNT-TCFs prepared by group 2 sloution,as substrates to grow GaN flim.The effects of TMGa flow rate and growth temperature on GaN film were investigated to inquiry optimal growth conditions.RHEED images show that GaN has the best crystallinity when the TMGa flow rate is 1.0 sccm and the growth temperature is300?.PLspectrum shows that the amorphous GaN film is formed when the TMGa flow rate is 0.8sccm and the growth temperature is 300?.I-V curve shows that the heterojunction between CNT-TCFs and GaN film is ohmic contact.