Haruyoshi Yamanaka

Variation of Liquid and Solid Compositions during LPE Growth from a Ternary Component Solution

A generalized calculation is presented to predict the variation of liquid and solid compositions during the liquid phase epitaxial growth from a ternary component solution under an equilibrium condition. Basic equations describing the fractional changes of liquid components are derived for the continuous process. Starting at a given initial condition the calculation based on an iterative procedure is carried out along on the theoretical liquidus surface with no adjustable parameters. The theory is applied to the growth of Ga1-XAlXAs as an example, resulting in good agreement with the experimental data.

A GaP monolithic numeric display with internal reflection facets

High brightness monolithic displays of GaP LEDs with slanting back surface facets which serve as self-reflection mirrors have been fabricated. A major fraction of radiation from the junction is so efficiently reflected by the slanting sides of the mesa-shaped segments that the out-coming beams can be confined into narrow regions. In fabrications of the devices, the wire-bonding process has been eliminated in such a way that the electrode contact to the n-region is also led from the same surface of the wafer as the p-contacts through an intentionally shorted p-n junction. Consequently, there is no electrode area which may shade the radiation on the light emitting surface. The structure gives an improvement in optical isolation as well as in external intensity, resulting in well-defined display patterns with high brightness.

Thickness dependence of output power and response time of double-heterostructure LED's.

The output power and the response time of a surface-emitting DH-LED are obtained theoretically by solving diffusion equations for excess electrons in terms of the active layer geometry. A significant difference in the output power is found between an n-side up diode and a p-side up diode owing to absorption loss in the active layer. The optimum thickness for each type is predicted. It is also shown that the sinusoidal modulation bandwidth and the rise time strongly depend on the active layer thickness as well as the interface recombination velocity. The analytical results are in agreement with experiment.