Research On Deep-ultraviolet Detector Arrays Based On BN Thin Films

With the continuous development of information science,the research of semiconductor devices based on new materials has become an inevitable trend.Among all kinds of new semiconductor materials,hexagonal boron nitride has attracted much attention because of its wide band-gap,high thermal conductivity,two-dimensional properties and many other advantages.The detection range of the deep UV detector array based on the hexagonal boron nitride film can cover the range of 200-220 nm,in which the present commercial UV detector has weak response.The deep UV detector array can be fully applied in the fields of UV short distance secure communication,shipboard guidance,the ozone layer monitoring and water pollution treatment.This dissertation studies to realize the deep UV detection array based on the hexagonal boron nitride film,including the preparation technology of the hexagonal boron nitride film,the contact characteristics between the hexagonal boron nitride and the metal,and the deep UV detector array in turn.Firstly,the hexagonal boron nitride nanocrystalline film was successfully prepared by magnetron sputtering,and the boron-rich problem of the sample was effectively suppressed by improving the process parameters.Secondly,based on the hexagonal boron nitride film,the surface work function and energy band position of boron nitride were analyzed,and the contact type between the copper electrode and the hexagonal boron nitride film was confirmed as Schottky contact.Finally,the design and implementation deep of UV detection arrays based on hexagonal boron nitride and a matching driving circuit were carried out.In this dissertation,the relationship between the growth mechanism of boron nitride under the magnetron sputtering method and the controllable parameters of the equipment is clarified,and the technological parameters of the process are continuously explored to suppress the negative effects of boron-rich problem.The hexagonal boron nitride thin film has been prepared successfully at a growth rate of about 120nm/h,its atoms are close to stoichiometric ratio,which are of great significance for the future research.Furthermore,according to the first principle and the experimental results,the position of the energy band of h BN relative to the vacuum energy level is determined.The Schottky contact model of copper and h BN is established and verified by applying the semiconductor energy band theory.The typical semiconductor parameters of h BN and the contact properties between h BN and metal electrode are cross verified.It is confirmed that the surface roughness of the film is about 1.13 nm,the relative dielectric function's long wavelength limit is about 3.07,the band gap width is about 5.86 e V,the conduction band position is about-3.83 e V,the valence band position is about-9.69 e V,the surface work function is about 6.76 e V.The Schottky barrier height of h BN/Cu junction is estimated to be 0.59 ev.Furthermore,the performance of the device are studied.The photoelectric responsibility of the 4 × 4 detector array is over 20 u A / W within the incident wavelength range of 200nm-230 nm,the noise power level is in the range of 1-10 n W,and the estimation of the detector's internal gain is 6×10E-3.Finally,a driving circuit based on STM32 microcontroller is designed and implemented,which is matched with the deep UV detector arrays.The rising edge of the photoelectric response is 7.6ms and the falling edge is 25.3ms.