Metalorganic chemical vapor deposition of indium nitride and indium gallium nitride thin films and nanostructures for electronic and photovoltaic applications.

摘要

Single and multi-junction InxGa1-xN solar cell devices were modeled in one dimension using MEDICI device simulation software to assess the potential of InxGa1-xN-based solar cells. Cell efficiencies of 16 and 27.4%, under AM0 illumination were predicted for a single and a 5-junction InxGa1-xN solar cell, respectively. Phase separation of InxGa1-xN alloys is determined to have little to no negative effects on the solar cell efficiency.; InxGa1-xN alloys were grown by MOCVD over the entire compositional range (0 ≤ x ≤ 1) and phase separation was analyzed with respect to substrate material and growth temperature. A low deposition temperature of 530°C was used to produce metastable InxGa1-xN/c-Al 2O3 thin films over the entire compositional range, which was demonstrated for the first time by MOCVD. The use of higher deposition temperature and closely lattice matched substrates resulted in phase separated films. Substrates with a larger lattice mismatch (c-Al2O3 ) introduce strain in InxGa1-xN which helps to stabilize the film, however, at the expense of crystalline quality.; Growth of InN nanowires by MOCVD was controlled without the use of templates or catalysts by varying the inlet flow pattern, N/In ratio, growth temperature, and substrate material. A VLS growth mechanism is proposed, however, a VS growth mechanism can be achieved at high N/In ratios. SEM and TEM analysis revealed a core-shell nanowire structure with a single crystal InN core and a poly-crystalline In2O3 shell. Nanowire growth occurs along the [0002] direction with diameters and lengths ranging from 100 to 300 nm and 10 to 40 mum, respectively for a 1 hr growth.; H-MOCVD growth of InN nano- and microrods occurred on different substrates and the nanorod structure was studied by TEM. The polarity of the substrate directly affected the nanorod tip shape and prismatic stacking faults are suggested as the cause for the flower-like growth habit. Variation of growth parameters, such as temperature, N/In ratio, and Cl/In ratio proved to be ineffective at changing the aspect ratio of the nanorods. Increased growth duration produces microrod size dimensions regardless of the chosen growth conditions.