Defect selective etching of GaAsyP1−y photovoltaic materials

Rapid and accurate threading dislocation density (TDD) characterization of direct-gap GaAsyP1−y photovoltaic materials using molten KOH defect selective etching (DSE) is demonstrated. TDDs measured using molten KOH DSE show close agreement with those from both electron beam-induced current mapping and planar view transmission electron microscopy, provided TDD<107 cm−2. H3PO4 DSE is also demonstrated as an accurate method for characterizing TDD of GaP substrates. Taken together, the DSE methods described here enable TDD characterization over large areas (>105 µm2) from substrate to GaAsyP1−y device layer.