Fabrication And Properties Of GaN,InN Nanomaterials

Group?nitride semiconductors have wide bandgap of 0.64⁶.2 eV by proper alloying,which can be widely used in solar cells,the light-emitting devices from near infrared to ultraviolet,high-temperature,high-pressure,high-frequency and high-power devices and other fields.Compared with their thin film counterpart,nanostructured III-nitride semiconductors are rich in morphology and exhibit superior physical,chemical,and optoelectrical properties.In order to explore the applications of?-nitrides on photodetection and electrochemical energy storage devices,GaN and InN nanomaterials are systematically studied.Combined with the structural characteristics of nanomaterials,different devices are designed and constructed.The main contents and results are summarized as follows:1.GaN nanostructures have been prepared by chemical vapor deposition method using GaCl₃/Ga₂O₃ as the precursor of Ga,and NH₃ as the precursor of N.The effects of the temperatures,gas flow rates,the distance between the source and the substrate,growth time and the Au catalyst on the morphology and structural characteristics of GaN nanomaterials have been investigated indetail.GaN nanorods grown along the,-direction can be obtained under optimum growth parameters when using GaCl₃ precursor.GaN nanowires,tower-like nanorods and nanosheets grown from Ga₂O₃ precursor follows the vapor-liquid-solid growth mechanism with the assist of Au catalyst.The morphological and optical properties of GaN nanostructures are highly depended on?/?ratio of the precursors.As the?/?ratio increasing,the morphology of GaN changes from nanowires to tower-like nanorods.The obtained GaN nanorods exhibit good monocrystal quality and strong near-band edge luminescence at 364 nm.2.The preparation and properties of InN nanomaterials are investigatd using InCl₃ as the precursor.The evolution of InN nanostructures with the main growth parameters,including growth temperature,gas flow rates?Ar carrier gas and NH₃?and the Au catalyst has been studied.The suitable growth temperature of InN nanostructures is about 600-700?.Column-like InN nanostructures with smooth surface and high quality are obtained through catalyst-free chemical vapor deposition method,exhibiting a PL emission band centered at 570 nm.While,novel Au-embedded In₂O₃ nanowires are obtained with the assist of Au catalyst at750?.Catalytic Au is found discontinuously distributed along the axial direction in the form of nanodots.The novel Au-embedded In₂O₃ nanowires are co-catalyzed by ammonia and Au during the nucleation and formation processes.3.The application of GaN nanostructures in UV detection and electrochemical energy storage are explored.?1?Metal-semiconductor-metal?MSM?structured UV detector based on the GaN nanorods has been fabricated,and the photodetection performance of the device has been studied.The tower-like GaN nanorods UV detector exhibits outstanding detection performance and fast sensing property.The rise time and decay time of photodetector are less than 82 and 164 ms,respectively.When the bias voltage is 3 V,the photocurrent and responsivity are 52?A and 64.2 mA/W,respectively.?2?Based on the characteristics of large aspect ratio,high electron mobility,good electrochemical reversibility and thermal stability,GaN nanowires are considered to be a potential candidate of electrode material for energy storage application.The electrochemical properties and energy storage mechanism of GaN and GaN-MoS₂ nanowires electrodes have been investigated.The GaN and GaN-MoS₂nanowires electrodes exhibit Faradaic behavior and fast charge/discharge ability.When the current density is 1 mA cm^-2,the GaN and GaN-MoS₂ nanowires show high energy storage characteristics with the capacities of 128.8 and 173.4 mC cm^-2,respectively.