The intermediate band approach in the third solar cell generation context

Hydrogenated amorphous silicon thin films were deposited using a high pressure sputtering (HPS) system. In this work, we have studied the composition and optical properties of the films (band-gap, absorption coefficient), and their dependence with the deposition parameters. For films deposited at high pressure (1 mbar), composition measurements show a critical dependence of the purity of the films with the RF power. Films manufactured with RF-power above 80W exhibit good properties for future application, similar to the films deposited by CVD (Chemical Vapor Deposition) for hydrogenated amorphous silicon.

Por Leocadia Mey y de Mur, con Rodrigo Perez, curador de Francisco Olgiat

Port. con grab. xil. representando a la Inmaculada

Electrical decoupling effect on intermediate band Ti-implanted silicon layers

We investigated the electrical transport properties of ultraheavily Ti-implanted silicon layers subsequently pulsed laser melted (PLM). After PLM, the samples exhibit anomalous electrical behaviour in sheet resistance and Hall mobility measurements, which is associated with the formation of an intermediate band (IB) in the implanted layer. An analytical model that assumes IB formation and a current limitation effect between the implanted layer and the substrate was developed to analyse this anomalous behaviour. This model also describes the behaviour of the function V/Delta V and the electrical function F that can be extracted from the electrical measurements in the bilayer. After chemical etching of the implanted layer, the anomalous electrical behaviour observed in sheet resistance and Hall mobility measurements vanishes, recovering the unimplanted Si behaviour, in agreement with the analytical model. The behaviour of V/Delta V and the electrical function F can also be successfully described in terms of the analytical model in the bilayer structure with the implanted layer entirely stripped.

Células solares de banda intermedia

Las células solares de banda intermedia se inventaron en España. Constituyen una propuesta para aumentar la eficiencia de las células solares por encima del límite de Shockley y Queisser para células de un solo gap. El número de ideas para llevarlas a la práctica (desde la utilización de puntos cuánticos a la implantación selectiva de impurezas) se ha ido expandiendo a medida que nuestra comprensión ha ido aumentando. En este artículo repasamos el concepto de célula solar de banda intermedia y algunas de estas ideas para llevarla a la práctica.

Far infrared photoconductivity in a silicon based material: vanadium supersaturated silicon

We have analyzed the spectral sub-bandgap photoresponse of silicon (Si) samples implanted with vanadium (V) at different doses and subsequently processed by pulsed-laser melting. Samples with V concentration clearly above the insulator-metal transition limit show an important increase of the photoresponse with respect to a Si reference sample. Their photoresponse extends into the far infrared region and presents a sharp photoconductivity edge that moves towards lower photon energies as the temperature decreases. The increase of the value of the photoresponse is contrary to the classic understanding of recombination centers action and supports the predictions of the insulator-metal transition theory.

Ruling out the impact of defects on the below band gap photoconductivity of Ti supersaturated Si

In this study, we present a structural and optoelectronic characterization of high dose Ti implanted Si subsequently pulsed-laser melted (Ti supersaturated Si). Time-of-flight secondary ion mass spectrometry analysis reveals that the theoretical Mott limit has been surpassed after the laser process and transmission electron microscopy images show a good lattice reconstruction. Optical characterization shows strong sub-band gap absorption related to the high Ti concentration. Photoconductivity measurements show that Ti supersaturated Si presents spectral response orders of magnitude higher than unimplanted Si at energies below the band gap. We conclude that the observed below band gap photoconductivity cannot be attributed to structural defects produced by the fabrication processes and suggest that both absorption coefficient of the new material and lifetime of photoexcited carriers have been enhanced due to the presence of a high Ti concentration. This remarkable result proves that Ti supersaturated Si is a promising material for both infrared detectors and high efficiency photovoltaic devices.

Relacion i memorial ajustado a ... los autos, e informaciones hechas por ... Don Rodrigo Marin i Rubio Obispo ... de Jaen, i a pedimiento de la ... i que se declaren por de dicho santo martyr los huessos que se hallaron en la bobeda de el altar mayor de la ... cathedral de Baeza ... el año ... de mil setenciento i veinte i nueve

Sign.: A-L2

The Gothic Ribbed vaults in Rodrigo Gil de Hontañón

The Gothic Ribbed vaults in Rodrigo Gil de Hontañón. Second International Congress on Construction History. Construction History Society. Cambridge. Reino Unido. Vol: III. Pags: 2415-2431. ISBN. 0-7017-0205-2

Oracion lamentable a la muerte de Don Rodrigo Calderon que fue degollado en la plaça mayor de Madrid a 21 de Octubre 1621

El pie de imp. consta en colofón

Double ion implantation and pulsed laser melting processes for third generation solar cells

In the framework of the third generation of photovoltaic devices, the intermediate band solar cell is one of the possible candidates to reach higher efficiencies with a lower processing cost. In this work, we introduce a novel processing method based on a double ion implantation and, subsequently, a pulsed laser melting (PLM) process to obtain thicker layers of Ti supersaturated Si. We perform ab initio theoretical calculations of Si impurified with Ti showing that Ti in Si is a good candidate to theoretically form an intermediate band material in the Ti supersaturated Si. From time-of-flight secondary ion mass spectroscopy measurements, we confirm that we have obtained a Ti implanted and PLM thicker layer of 135 nm. Transmission electron microscopy reveals a single crystalline structure whilst the electrical characterization confirms the transport properties of an intermediate band material/Si substrate junction. High subbandgap absorption has been measured, obtaining an approximate value of 104 cm−1 in the photons energy range from 1.1 to 0.6 eV.

Towards a new generation of solar cells: silicon supersaturated with titanium or vanadium

We have analyzed the spectral sub-bandgap photoresponse of silicon (Si) samples implanted with vanadium (V) and titanium (Ti) at different doses and subsequently processed by pulsed-laser melting.

Intermediate band solar cells. The transition metal supersaturated Silicon approach

Within the framework of the third solar cell generation some new ideas to enlarge the spectral response of the solar cells toward the infrared have been proposed. Among them the inclusion of an Intermediate Band (IB) seems to be very promising. This paper will deal with one of the ways to generate the IB namely the deep level center approach. We will discuss not only its existence but also the carriers lifetime recovery which is necessary to obtain the expected increase of the solar cell efficiency.

Palacio de los Castro (Ciudad Rodrigo)

Palacio de los Castro (Ciudad Rodrigo)

La capilla del castillo de Brihuega y las edificaciones de don Rodrigo Jiménez de Rada

La capilla del castillo de Brihuega y las edificaciones de don Rodrigo Jiménez de Rada

Wind pumps for irrigating greenhouse crops: Comparison in different socio-economical frameworks

A methodology is applied for economic evaluation of water pumping technologies. Different socioeconomic frameworks are considered for Spain, Cuba and Pakistan. The levelised cost of energy is used to determine the best technology. Wind speed, distance to grid, water storage size and elevation are considered. The water elevation has greater influence on wind pumps than on solar PV pumping.