Fabrication and electrical characterization of 0.55 eV n-on-p InGaAs thermophotovoltaic devices

Results are presented on the characterization and testing of lattice mismatched 0.55 eV InGaAs/InP thermophotovoltaic (TPV) cells. A robust cell fabrication technique amenable to high throughput production is presented. A versatile light and dark I-V set up capable of fast screening of the TPV cells and an innovative approach for screening high performance cells are presented. The authors also report on the effect of lattice matched InAsP and InAlAs back surface field on the performance of the TPV cells

Cross-sectional electrostatic force microscopy of thin-film solar cells

In a recent work, we showed that atomic force microscopy (AFM) is a powerful technique to image cross sections of polycrystalline thin films. In this work, we apply a modification of AFM, namely, electrostatic force microscopy (EFM), to investigate the electronic properties of cleaved II-VI and multijunction thin-film solar cells. We cleave the devices in such a way that they are still working with their nominal photovoltaic efficiencies and can be polarized for the measurements. This allows us to differentiate between surface effects (work function and surface band bending) and bulk device properties. In the case of polycrystalline CdTe/CdS/SnO2 /glass solar cells, we find a drop of the EFM signal in the area of the CdTe/CdS interface (±50 nm). This drop varies in amplitude and sign according to the applied external bias and is compatible with an n-CdS/p-CdTe heterojunction model, thereby invalidating the possibility of a deeply buried n-p CdTe homojunction. In the cas e of a triple-junction GalnP/GaAs/Ge device, we observe a variation of the EFM signal linked to both the material work-function differences and to the voltage bias applied to the cell. We attempt a qualitative explanation of the results and discuss the implications and difficulties of the EFM technique for the study of such thin-film devices

Growth and characterization of GaPNAs on Si

Growth and charaterization of GaPNAs on S

Solid-phase crystallization of evaporated silicon thin films on glass for photovoltaics: A combined SEM and TEM study

10.1117/12.823622Proceedings of SPIE - The International Society for Optical Engineering7409-PSIS

Characterization of evaporated solid-phase crystallized silicon thin-film solar cells on glass

10.1109/PVSC.2009.5411644Conference Record of the IEEE Photovoltaic Specialists Conference000445-000449CRCN

Improved current collection in WO3 Mo WO3 bilayer photoelectrodes

We report on the incorporation of molybdenum into tungsten oxide by co sputtering and its effect on solar powered photoelectrochemical PEC water splitting. Our study shows that Mo incorporation in the bulk of the film WO3 Mo results in poor PEC performance when compared with pure WO3, most likely due to defects that trap photo generated charge carriers. However, when a WO3 Mo WO3 bilayer electrode is used, a 20 increase of the photocurrent density at 1.6 V versus saturated calomel reference electrode is observed compared with pure WO3. Morphological and microstructural analysis of the WO3 Mo WO3 bilayer structure reveals that it is formed by coherent growth of the WO3 Mo top layer on the WO3 bottom layer. This effect allows an optimization of the electronic surface structure of the electrode while maintaining good crystallographic properties in the bul