Crystallographic dependent in-situ CBr4 selective nano-area etching and local regrowth of InP/InGaAs by MOVPE

• Study of MOVPE selective etching of InP by CBr4 and growth on nanometer scale.
• Observation of different etching behavior along the [0−1−1] and [011̄] directions.
• With regards to the etched profiles, the directly grown InGaAs layers varied in shapes.
• A red-shift of over 125 nm seen for InGaAs/InP QW between perpendicular directions.

Selective area etching and growth in the metalorganic vapor phase epitaxy (MOVPE) reactor on nano-scale structures have been examined. Using different mask orientations, crystallographic dependent etching of InP can be observed when carbon tetrabromide (CBr4) is used as an etchant. Scanning Electron Microscopy (SEM) investigation of etch profiles showed formation of a U-shaped groove along the [01̄1̄] direction, terminated by {111}B planes with an ~15 nm {100} plateau and transitional {311}B planes, developed in a self-limiting manner. In the perpendicular direction [01̄1] etching with a dominant lateral component driven by fast etched {111}A and {311}A side planes was observed. A directly grown single InGaAs QW in the etched grooves demonstrated different QW profiles: a crescent-shaped on {311}B and {100} planes (along the [01̄1̄] direction) and two separated quarter-circle curvatures grown preferably on {311}A along [01̄1̄]. Room temperature micro-photoluminescence measurements indicated a wavelength red-shift in over 125 nm along [01̄1̄] comparing to [01̄1], which is related to both growth enhancement and composition variation of the grown material.