A co-solvent, dimethylsulfoxide (DMSO), is added to the aqueous chemical "bath" deposition (CBD) process used to grow ZnOS buffer layers for thin film Cu2ZnSnSe4 (CZTSe) solar cells. Device performance improves markedly as fill factors increase from 0.17 to 0.51 upon the co-solvent addition. X-ray photoelectron spectroscopy (XPS) analyses are presented for quasi-in situ CZTSe/CBD-ZnOS interface...

GRB 971214 is the third gamma ray burst for which an optical afterglow has been detected. I show that the spectrum of this afterglow (optical and X-ray) is inconsistent with the relativistic blast-wave model unless a significant source of extinction is introduced. Assuming that a single absorber exists at redshift z, I find that its V -band absorption magnitude at this redshift is AV (z) = 1.00...

Device modeling and simulation of a mechanically stacked CuGaSe2/Cu(In1-x,Gax)Se2 (CGS/CIGS) tandem solar cell have been carried out in this study. The physical model consists of a CIGS bottom cell with a double graded band-gap profile in the space charge region (SCR) and the backside of the absorber layer and a uniform band-gap CGS top cell. By varying the absorber layer thickness of the CGS t...

We present a metamaterial absorber detector array that enables room-temperature, narrow-band detection of gigahertz (GHz) radiation in the S band (2-4 GHz). The system is implemented in a commercial printed circuit board process and we characterize the detector sensitivity and angular dependence. A modified metamaterial absorber geometry allows for each unit cell to act as an isolated detector ...

This paper presents the characterization of integrated micromachined waveguide absorbers in the frequency band of 220 to 325 GHz. Tapered absorber wedges were cut out of four different commercially available semi-rigid absorber materials and inserted in a backshorted micromachined waveguide cavity for characterization. The absorption properties of these materials are only specified at 10 GHz, a...