Novel semiconductors and heterostructures

Abstract

Molecular beam epitaxy and metalorganic chemical vapor deposition in conjunction with modulated doping continue to contribute new classes of electronic and optoelectronic materials and devices. Recent advances include new heterostructure infrared detectors which exploit the flexibility of growth techniques to tailor detector response to particular wavelengths out to 12 μ and beyond. These detectors utilize intraband transitions in quantum wells and superlattices. They can be implemented in widegap materials like AlxGa1−xAs/GaAs with fewer materials problems than narrow gap materials like HgxCd1−xTe. Quantitatively predictable spectral response has resulted from improved understanding of device physics issues, including the analysis of electron–electron exchange interactions in doped quantum wells. Progress has also been made in quantitative analysis of the effects of interface roughness on electronic states in quantum wells. These recent advances are important not only for detectors, but also for ultrahigh speed electronic devices employing resonant tunneling in heterostructures.