Morphological instability in InAs/GaSb superlattices due to interfacial bonds.

Synchrotron x-ray diffraction is used to compare the misfit strain and composition in a self-organized nanowire array in an InAs/GaSb superlattice with InSb interfacial bonds to a planar InAs/GaSb superlattice with GaAs interfacial bonds. It is found that the morphological instability that occurs in the nanowire array results from the large misfit strain that the InSb interfacial bonds have in the nanowire array. Based on this result, we propose that tailoring the type of interfacial bonds during the epitaxial growth of III-V semiconductor films provides a novel approach for producing the technologically important morphological instability in anomalously thin layers.

Mid-infrared w quantum-well lasers for noncryogenic continuous-wave operation.

We review the recent progress of electrically injected and optically pumped mid-IR lasers based on antimonide quantum wells with the type II W configuration. W quantum-well diodes have achieved cw operation up to 195 K at lambda = 3.25 mum. Optically pumped devices that employ the diamond pressure bond heat sink have reached 290 K at 3 mum and 210 K at 6 mum. Pulsed power conversion efficiencies of up to 7% at 220 K have been attained by use of an optical pumping injection cavity approach, in which an etalon cavity for the pump beam significantly enhances its absorptance. The angled-grating distributed-feedback configuration has been used to obtain near-diffraction-limited output for an optical pumping stripe width of 50 mum.

Melanocytoma of the ciliary body with scleral extension.

A 35-year-old woman had a circumscribed pigmented scleral lesion overlying a pigmented mass in the ciliary body and trabecular meshwork. Sclerectomy and iridocyclectomy were performed. Histologically, the lesion proved to be a melanocytoma. This represents to our knowledge the fourth reported case of scleral extension of a ciliary body melanocytoma.

Axenfeld's anomaly associated with Down's syndrome.

We report a case of a patient with Down's syndrome and keratoconus with acute hydrops who was incidentally noted to have Axenfeld's anomaly. We also review the systemic abnormalities associated with Axenfeld's anomaly and the implications of the diagnosis. To our knowledge, Axenfeld's anomaly has not previously been reported in association with Down's syndrome.