Characterization of InGaAsP/InP double-heterostructure wafers grown by metalorganic vapor phase epitaxy for semiconductor lasers by photoluminescence investigation with high-power YAG-laser excitation

Abstract

The photoluminescence (PL) spectrum distribution of a low-pressure metalorganic vapor-phase epitaxy grown wafer with an InGaAsP/InP double heterostructure (DH) was measured under the irradiation of a high-power Nd-YAG laser. The two-dimensional distribution profiles of the PL intensity and peak wavelength in the wafer are discussed in terms of the temperature profile on the substrate surface during growth. A change in the decomposition ratio of the reaction gas due to a temperature change on the substrate surface was found to cause the compositional (PL wavelength) distribution on the wafer and the subsequent lattice mismatch, which is considered to be the main factor influencing PL characteristics. Laser diodes (LDs) were fabricated from the DH wafer, and both PL and LD characteristics were compared. The PL intensity was found to be in reciprocal proportion to the threshold current of the LD, and the PL peak wavelength had a parallel red shift of 10–30 nm to the lasing wavelength. As a result, the LD characteristics, the threshold current, and the lasing wavelength could be predicted from the high-power PL measurements of the as-grown wafer before the LD fabrication processing.