Testing And Characterization Of GaN/AlGaN Quantum Well Infrared Detectors

Infrared (IR) detectors and ultraviolet (UV) detectors are widely used inmilitary and civil use, and play an irreplaceable role. As a representative of thethird generation semiconductor， GaN-based semiconductor devices offer apossibility to realize integrated detection of IR and UV radiation, whereAlGaN/GaN quantum well structures have unparalleled advantages in terms ofachieving infrared detection. However, studies mainly have focused on shortwavelength band of around1.55μm and have been few relevant reports for3~5μm atmospheric window band which has a very wide range of applications inthe low-loss optical fiber communications, military and civilian detection.The purpose of the project is realizing to achieve blind UV-MIR two-colordetectors, this thesis has carried out the research work on the materialcharacterization, calculation of energy band, electronic transport properties,device work principle, and photo-current detection of the GaN/AlGaN quantumwell infrared detectors. Firstly, the subband transitions and electron transportproperties in the GaN/AlGaN quantum wells have been simulated by theCrosslight software. The effects of structural parameters of quantum wells (Al-component, well width, doping and polarization field strength) on theintersubband transitions and electron transport properties have been investigatedbased on the finite element analysis and the structure parameters have beenoptimized. Secondly, the structure, size and the crystal quality of the quantumwell materials have been characterized by the high resolution X-ray diffraction(HRXRD).The luminescent properties, energy band distribution and polarizationin the quantum wells have been characterized by photoluminescence (PL),Raman spectroscopy and IR absorption (transmission) spectrum. Finally, thesubband transitions and electron transport properties of the wave-guide couplingGaN/AlGaN quantum well structures have been characterized employing Fourier spectroscopy, polarization system, cryogenic system and electrical system.Through measuring the optical and electrical properties of the GaN/AlGaNquantum well structures, the physical mechanisms in the structures have beeninvestigated and the material and device structures have been optimized.