Gallium arsenide based semiconductor laser design and growth by metal-organic chemical vapor deposition.

摘要

This dissertation presents research projects with the common theme: novel GaAs based device structures grown by metal organic chemical vapor deposition (MOCVD).; Vertical-cavity surface-emitting laser (VCSEL) arrays for application to free space optical interconnections were manufactured. The design of VCSELs with oxide apertures is discussed. Low-threshold, uniform 20x20 arrays with a 3dB frequency of up to 5 GHz were demonstrated with MOCVD grown epi structures.; Novel designs for high efficiency, high-power edge emitting lasers are discussed. Excess voltage drop is identified as an important cause limiting the efficiency. First, an asymmetric quantum well with a small conduction band offset in the n side and small valence band offset in the p side is proposed. Second, a transverse junction structure which has the carriers injected from the sides of the QW is also proposed. Simulations of both structures predict 80% overall efficiency. Preliminary selective area growth tests for the transverse junction structure were preformed.; Compliant substrates are evaluated to extend the use of GaAs based materials to longer wavelengths. Thick InGaAs layers with InGaAs multiple quantum wells were grown on compliant substrates which were made by wafer bonding a thin GaAs layer on a thick GaAs substrate. A material quality improvement was observed compared with the same epi structure grown directly on GaAs substrates, but the improvement is too small for real device applications, so the limitations of compliant substrates are discussed.; Preliminary research findings on adaptive designed asymmetric electroabsorption modulators are presented. Control of intentional and background doping in the MOCVD growth of AlGaAs is discussed. The doping behaviors of Zn and Si in AlGaAs under typical growth conditions and at low V/III ratios were investigated. Carbon doping of AlGaAs by CBr4 was realized. The AlGaAs growth rate and lattice constant are influenced by the CBr4 doping. MOCVD grown Al0.3GaAs with low background doping of 1∼2E15 cm-3 was achieved by using TMAl, TEGa and Arsine as sources.