Role of molecular beam epitaxy in the field of optoelectronics

Abstract

This article reviews the role of molecular beam epitaxy (MBE) in the field of optoelectronics. In the past 25 years, this crystal growth technology has helped researchers to investigate important physical phenomena related to materials properties. In particular, success in engineering the band structure and refractive index was a key to the exploration and development of carrier transport devices such as high-mobility, bipolar and tunnel transistors, as well as optoelectronic elements such as LEDs, lasers, modulators and photodetectors. Because of its relatively simple growth process, excellent growth control and ability to characterize growth-related phenomena in situ, MBE initiated many important research fields such as GaAs on silicon, fast optical switches and detectors, and vertical cavity and edge-emitting quantum well lasers, particularly in the GaAs/AlGaAs materials system. In addition, relatively unexplored systems such as II/VI materials, nitrides or even Si/Ge heterostructures, are currently hot topics among MBE crystal growers. Over the years, the division of the roles of MBE as a research and prototyping tool and metal-organic vapor-phase epitaxy (MOVPE) as a production tool has become well established. However, for certain production processes, specifically compact disc and 980 nm Er-fiber pump lasers, MBE has been proved to be as good or better than MOVPE, even when high throughput is a necessity. New fields, such as devices based on very precise vertical Fabry-Perot cavity designs and low-temperature GaAs, are emerging in which the uniform thickness control, in situ monitoring capability and low-temperature growth ability of MBE offer clear superiority over MOVPE for eventual production.