Net Acceptor Density Research Articles

Interpretation of anomalous layers at GaAs n +−n − step junctions

Anomalous interfacial layers at GaAs n +−n − step junctions have been widely interpreted from capacitance-voltage (CV) measurements as 2–4 micro thick high resistivity regions with a net donor impurity density on N D − N A ∼10 13 −10 14 cm −3. We present evidence that these impurity layers are in fact ≈ 0.2−2 microns thick with a net acceptor density ranging from 10 14−10 16 cm −3. The carrier density due to these layers is strongly voltage dependent and accounts for the anomalous CV characteristics observed.