Molecular Beam Epitaxy Growth and Characterization of Mid-IR Type-II 'W' Diode Lasers; Journal article

摘要

Type II 'W' diodes designed for emission at the spectral line of methane (3.31 micrometer) when operated near 80 K were grown on a compact 2IT RIBER molecular beam epitaxy system. Photoluminescence and cross-sectional scanning tunneling microscopy were used as tools to improve the growth quality of these structures. The diodes exhibited very low housing thresholds at T=80 K (24-40 A/cm(2)), although further development will be required to enhance the characteristic temperature (T(o) approx. 40 K) and the maximum operating temperature (approx. 190 K). The lasers had favorable internal losses at all T up to 190 K (approx. 7 cm(-1)), and favorable internal efficiencies at low T (up to 85%). The I-V characteristics of nonlasing test structures were improved substantially by adding n-side 'transition' regions that smoothed out abrupt steps in the conduction-band offset.