Edge surfaces in lithographically textured molybdenum disulfide.

Lithographic techniques were used to expose edge surfaces in layered molybdenum disulfide single crystals. This microstructuring produced ideal samples for the study of the surface morphology and electronic structure of this catalytically important material. The optical absorption that was measured at mid-gap increased by two orders of magnitude after texturing.

Maximum statistical increase of optical absorption in textured semiconductor films.

Complete statistical randomization of the direction of propagation of light trapped in semiconductor films can result in a large absorption enhancement. We have employed a calorimetric technique, photothermal deflection spectroscopy, to monitor the absorption of alpha-SiH(x) films textured by the natural lithography process. The observed enhancement factors, as high as 11.

Thermodynamics of daylight-pumped lasers.

We cast the problem of very-low-threshold, daylight-pumped lasers in a general thermodynamic framework. We calculate that the requirements to reach threshold are that the Stokes shift of such a laser be greater than 13.3kT and that the absorption ratio of the pump/emission band and the geometrical aspect ratio both be greater than exp (13.