This is a 1992 Presidential Faculty Fellow Award (PFF). The optical and electronic properties of compound semiconductors and their respective heterostructure systems are crucial for future high speed electronic optoelectronic, light-emitting display, and solar energy conversation applications. In order to exploit these properties fully, the five year research effort will be concentrated in two general areas of interest, namely, epitaxial crystal growth and basic materials properties of ternary alloys and heterostructures that contain combinations of the Column III elements Al, Ga, and In, and a single Column V element P, As, or Sb, and the device physics of vertical cavity quantum well lasers, modulators, switches, and optical interconnects.