| Arsenic incorporation and activation in HgCdTe were investigated primarily through crystal growth by molecular beam epitaxy, subsequent material characterizations and a proposed quasi-thermodynamic defect model. In situ arsenic p-type doping is required by a variety of opto-electronic devices, such as the HgCdTe-based photovoltaic infrared detectors. These sophisticated detectors required well-behaved and controlled doping levels. The new annealing and growth techniques proposed in this work show that arsenic could be used as a good p-type dopant during the molecular beam epitaxial growth. At high arsenic concentrations, the activation of arsenic in the HgCdTe epilayers drops drastically due arsenic self compensation. HgCdTe epilayers were characterized by Hall measurements, secondary ion mass spectroscopy, Fourier transform infrared, x-ray diffraction, Reflection high-energy diffraction, and etch pit densities. The cadmium composition was monitored using in situ spectral ellipsometry. |
