Ternary Nitride Semiconductors as Nonlinear Optical Materials

NZ Applied Technologies proposes to develop plasma-enhanced metalorganic chemical vapor deposition (PE-MOCVD) to create optically clear single crystal films of several unexplored ternary nitride semiconductors to study their nonlinear optical properties, and to use them for frequency doubling of visible and near IR lasers into wavelengths ranging from green to violet. Ternary nitrides appear to be excellent candidates for second harmonic generation (SHG) because they are transparent in the visible and, due to their noncentrosymmetric (rhombohedral) crystal structure, must exhibit birefringence; the latter is a basic requirement for phase-matching. Use of activated nitrogen from a plasma will permit them to be grown with low defect densities, a must for minimizing optical losses when configured as waveguides. The ability to produce these nitrides as waveguides will increase the interaction length between primary and secondary fields, giving significantly higher power conversion efficiency. Phase matching can further be enhanced by applying external fields transverse to the ternary waveguides. Phase I will determine the conditions needed to grow these new ternary nitride films. Grown films will be measured to determine structural, optical, and electrical properties. A simple second harmonic generation (SHG) experiment will be performed. In Phase II, growth conditions will be optimized and functioning SHG devices demonstrated.