Optical and electrical characteristics of GaAs/AlGaAs GRIN-SCH lasers grown selectively by MBE on SiO<inf>2</inf>-patterned substrate

Abstract

A GaAs/AlGaAs graded-index seperate confinement heterostructure (GRIN-SCH) laser is demonstrated by single selective molecular beam epitaxial (MBE) growth on SiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> -patterned GaAs substrate. The laser has a threshold current of 50 mA and lases in single longitudinal mode with a side suppression ratio of 95. The far-field pattern is primarily single-lobed up to 4 times threshold. Electrical test patterns show that the polycrystalline GaAs grown on SiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> near the boundaries with the single crystal conducts 20% of the current. However, by making the width of contact opening smaller than the width of the single crystal, the polycrystalline GaAs can provide very effective lateral current confinement. Lasers grown along [011] have lower threshold current than those along [ <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01\bar{1}</tex> ] because of less scattering loss of light.