Unraveling the Mechanism of Maskless Nanopatterning of Black Silicon by CF/H Plasma Reactive-Ion Etching.

The process of deep texturization of the crystalline silicon surface is intimately related to its promising diverse applications, such as bactericidal surfaces for integrated lab-on-chip devices and absorptive optical layers (black silicon-BSi). Surface structuring by a maskless texturization appeals as a cost-effective approach, which is up-scalable for large-area production. In the case of silicon, it occurs by means of reactive plasma processes (RIE-reactive-ion etching) using fluorocarbon CF and H as reaction gases, leading to self-assembled cylindrical and pyramidal nanopillars.

Characterization of angled tapered superluminescent LEDs.

We present a detailed analysis of the output beam of high-power edge-emitting angled tapered superluminescent LEDs (A-TSLEDs). A device model, including spontaneous and stimulated emission processes as well as the typical nonuniform carrier-density distribution due to current spreading and carrier diffusion, has been developed and used to interpret the experimentally obtained characteristics of inhouse-fabricated A-TSLEDs. The good match between measured and theoretical results indicates that the model reproduces the A-TSLED operation very satisfactorily and clearly explains the role of the collecting lens on the pronounced asymmetry of some of the measured optical intensity profiles.