A comparative study of p(+)n and n(+)p InP solar cells made by a closed ampoule diffusion

The purpose was to demonstrate the possibility of fabricating thermally diffused p(+)n InP solar cells having high open-circuit voltage without sacrificing the short circuit current. The p(+)n junctions were formed by closed-ampoule diffusion of Cd through a 3 to 5 nm thick anodic or chemical phosphorus-rich oxide cap layer grown on n-InP:S Czochralski LEC grown substrates. For solar cells made by thermal diffusion the p(+)n configuration is expected to have a higher efficiency than the n(+)p configuration. It is predicted that the AM0, BOL efficiencies approaching 19 percent should be readily achieved providing that good ohmic front contacts could be realized on the p(+) emitters of thickness lower than 1 micron

Effect of dislocations on properties of heteroepitaxial InP solar cells

The apparently unrelated phenomena of temperature dependency, carrier removal and photoluminescence are shown to be affected by the high dislocation densities present in heteroepitaxial InP solar cells. Using homoepitaxial InP cells as a baseline, it is found that the relatively high dislocation densities present in heteroepitaxial InP/GaAs cells lead to increased volumes of dVoc/dt and carrier removal rate and substantial decreases in photoluminescence spectral intensities. With respect to dVoc/dt, the observed effect is attributed to the tendency of dislocations to reduce Voc. Although the basic cause for the observed increase in carrier removal rate is unclear, it is speculated that the decreased photoluminescence intensity is attributable to defect levels introduced by dislocations in the heteroepitaxial cells

Progress in p(+)n InP solar cells fabricated by thermal diffusion

The performance results of our most recently thermally diffused InP solar cells using the p(+)n (Cd,S) structures are presented. We have succeeded in fabricating cells with measured AMO, 25 C V(sub oc) exceeding 880 mV (bare cells) which to the best of our knowledge is higher than previously reported V(sub oc) values for any InP homojunction solar cells. The cells were fabricated by thinning the emitter, after Au-Zn front contacting, from its initial thickness of about 4.5 microns to about 0.6 microns. After thinning, the exposed surface of the emitter was passivated by a thin (approximately 50A) P-rich oxide. Based on the measured EQY and J(sub sc)-V(sub oc) characteristics of our experimental high V(sub oc) p(+)n InP solar cells, we project that reducing the emitter thickness to 0.3 microns, using an optimized AR coating, maintaining the surface hole concentration of 3 x 10(exp 18)cm(sup -3), reducing the grid shadowing from actual 10.55 percent to 6 percent and reducing the contact resistance will increase the actual measured 12.57 percent AMO 25 C efficiency to about 20.1 percent. By using our state-of-the-art p(+)n structures which have a surface hole concentration of 4 x 10(exp 18)cm(sup -3) and slightly improving the front surface passivation, an even higher practically achievable AMO, 25 C efficiency of 21.3 percent is projected

Legislación laboral en seis países latinoamericanos. Avances y omisiones para una mayor equidad

Incluye BibliografíaEl presente estudio analiza las regulaciones nacionales en materia de Derecho del Trabajo en seis países de la región: Argentina, Chile, Costa Rica, Ecuador, El Salvador y Uruguay. Para ello, se comparan los aspectos más relevantes de los ordenamientos legales aplicables, sus disparidades, las políticas aplicadas por las entidades gubernamentales con competencia en la materia y las barreras que el ordenamiento jurídico impone agravando de ese modo la situación de facto que atraviesan las mujeres al momento de insertarse en el mercado de trabajo. En ese sentido, reviste especial interés el análisis de los principios del derecho laboral y la diferencia entre mujeres y hombres, situación que también es analizada en los Pactos y Tratados Internacionales de Derechos Humanos y en las Constituciones políticas de cada uno de los países seleccionados.A su vez, se presta especial consideración a los mecanismos legales que promueven o expulsan a las mujeres del mundo del trabajo, la existencia de normas que fomenten la armonización del trabajo remunerado y el trabajo reproductivo; el alcance de disposiciones que promuevan las responsabilidades familiares compartidas por la pareja; y la presencia de normas que conciban la maternidad como responsabilidad social y no individual. Por último se analiza especialmente el impacto de la flexibilización laboral implementada en los últimos años y las reformas en materia de seguridad social en cada uno de los países seleccionados. El estudio se inscribe en el marco del proyecto "Políticas laborales con enfoque de género" que ejecuta la Unidad Mujer y Desarrollo de la CEPAL, con apoyo de la Agencia Alemana de Cooperación Técnica (GTZ);. El proyecto busca fomentar la implementación de medidas a favor de la equidad de género en las políticas laborales, tanto a nivel nacional como local, y fortalecer la capacidad de diálogo y concertación en esta materia de las Oficinas de la Mujer, los Ministerios de Trabajo, otros actores institucionales gubernamentales y la sociedad civil

Status of diffused junction p+n InP solar cells for space applications

Recently, we have succeeded in fabricating diffused junction p(sup +)n(Cd,S) InP solar cells with measured AMO, 25 C open circuit voltage (V(sub OC)) of 887.6 mV, which, to the best of our knowledge, is higher than previously reported V(sub OC) values for any InP homojunction solar cells. The experiment-based projected achievable efficiency of these cells using LEC grown substrates is 21.3 percent. The maximum AMO, 25 C internal losses due to date on bare cells is, however, only 13.2 percent. This is because of large external and internal losses due to non-optimized front grid design, antireflection (AR) coating and emitter thickness. This paper summarizes recent advances in the technology of fabrication of p(sup +)n InP diffused structures and solar cells, resulted from a study undertaken in an effort to increase the cell efficiency. The topics discussed in this paper include advances in: (1) the formation on thin p(sup +) InP:Cd emitter layers, (2) electroplated front contacts, (3) surface passivation and (4) the design of a new native oxide/Al2O3/MgF2 tree layer AR coating using a chemically-grown P-rich passivating oxide as a first layer. Based on the high radiation resistance and the excellent post-irradiation annealing and recovery demonstrated in the early tests done to date, as well as the projected high efficiency and low-cost high-volume fabricability, these cells show a very good potential for space photovoltaic applications

Novel Passivating/Antireflective Coatings for Space Solar Cells

We are developing a novel process to grow passivating/antireflective (AR) coatings for terrestrial and space solar cells. Our approach involves a Room Temperature Wet Chemical Growth (RTWCG) process, which was pioneered, and is under development at SPECMAT, Inc., under a Reimbursable Space Act Agreement with NASA Glenn Research Center. The RTWCG passivating/AR coatings with graded index of refraction are applied in one easy step on finished (bare) cells. The RTWCG coatings grown on planar, textured and porous Si, as well as on poly-Si, CuInSe2, and III-V substrates, show excellent uniformity irrespective of surface topography, crystal orientation, size and shape. In this paper we present some preliminary results of the RTWCG coatings on Si and III-V substrates that show very good potential for use as a passivation/AR coating for space solar cell applications. Compared to coatings grown using conventional techniques, the RTWCG coatings have the potential to reduce reflection losses and improve current collection near the illuminated surface of space solar cells, while reducing the fabrication costs

Capital United? Business Unity in Regulatory Politics and the Special Place of Finance

While organized business is a key actor in regulatory politics, its influence is often conditional on the level of unity or conflict occurring within the business community at any given time. Most contemporary regulatory policy interventions put pressure on normal mechanisms of business unity, since they are highly targeted and sector-specific. This raises the question of how business unity operates across a highly variegated economic terrain in which costs are asymmetric and free-riding incentives are high. In the paper we empirically assess patterns of business unity within regulatory policymaking across different regulated sectors. Our analysis utilizes data from hundreds of regulatory policy proposals, and business community reactions to them in the telecommunications, energy, agriculture, pharmaceutical and financial sectors over a variety of institutional contexts. We find considerable empirical support for the ‘finance capital unity’ hypothesis – the notion that the financial sector enjoys more business unity than do other regulated sectors of the economy. When the financial sector is faced with new regulations, business groups from other sectors frequently come to its aid