Effects of Ga+ milling on InGaAsP Quantum Well Laser with mirrors etched by Focused Ion Beam

TL;DR

This study investigates how Ga+ Focused Ion Beam milling affects InGaAsP quantum well lasers, revealing changes in electrical and optical properties, with partial recovery after annealing, highlighting optical damage as the main impact.

Contribution

It provides the first detailed analysis of Ga+ FIB milling effects on InGaAsP quantum well lasers, including the impact on threshold current, efficiency, and emission spectrum.

Findings

7% increase in threshold current after milling

17% decrease in external quantum efficiency

15 nm blue shift in emission spectrum

Abstract

InGaAsP/InP quantum wells (QW) ridge waveguide lasers were fabricated for the evaluation of Ga+ Focused Ion Beam (FIB) milling of mirrors. Electrical and optical proprieties were investigated. A 7% increment in threshold current, a 17% reduction in external quantum efficiency and 15 nm blue shift in the emission spectrum were observed after milling as compared to the as cleaved facet result. Annealing in inert atmosphere partially revert these effects resulting in 4% increment in threshold current, 11% reduction in external efficiency and 13 nm blue shift with the as cleaved result. The current-voltage behavior after milling and annealing shows a very small increase in leakage current indicating that optical damage is the main effect of the milling process.