Abstract: A method of forming a photovoltaic device includes a plurality of quantum wells and a plurality of barriers. The quantum wells and barriers are disposed on an underlying layer. The barriers alternate with the quantum wells. One of the plurality of quantum wells and the plurality of barriers is comprised of tensile strained layers and the other of the plurality of quantum wells and the plurality of barriers is comprised of compressively strained layers. The tensile and compressively strained layers have elastic properties. The method includes selecting compositions and thicknesses of the barriers and quantum wells taking into account the elastic properties such that each period of one tensile strained layer and one compressively strained layer exerts substantially no shear force on a neighboring structure; providing the underlying layer; and forming the quantum sells and barriers on the underlying layer according to the derived compositions and thicknesses.

Abstract: A method of forming a photovoltaic device includes a plurality of quantum wells and a plurality of barriers. The quantum wells and barriers are disposed on an underlying layer. The barriers alternate with the quantum wells. One of the plurality of quantum wells and the plurality of barriers is comprised of tensile strained layers and the other of the plurality of quantum wells and the plurality of barriers is comprised of compressively strained layers. The tensile and compressively strained layers have elastic properties. The method includes selecting compositions and thicknesses of the barriers and quantum wells taking into account the elastic properties such that each period of one tensile strained layer and one compressively strained layer exerts substantially no shear force on a neighboring structure; providing the underlying layer; and forming the quantum sells and barriers on the underlying layer according to the derived compositions and thicknesses.

Abstract: A photovoltaic cell to convert low energy photons is described, consisting of a p-i-n diode with a strain-balanced multi-quantum-well system incorporated in the intrinsic region. The bandgap of the quantum wells is lower than that of the lattice-matched material, while the barriers have a much higher bandgap. Hence the absorption can be extended to longer wavelengths, while maintaining a low dark current as a result of the higher barriers. This leads to greatly improved conversion efficiencies, particularly for low energy photons from low temperature sources. This can be achieved by strain-balancing the quantum wells and barriers, where each individual layer is below the critical thickness and the strain is compensated by quantum wells and barriers being strained in opposite directions minimizing the stress. The absorption can be further extended to longer wavelengths by introducing a strain-relaxed layer (virtual substrate) between the substrate and the active cell.

Abstract: A container for fluent material has a limp flexible bottom and an upstanding limp flexible perimetral circular wall. The wall is kept upstanding by flexible support means between the upper edge of the wall and the upper horizontal member of a framework surrounding and spaced from the perimetral wall. The wall is of waterproof-coated woven synthetic fabric with the warp running lengthwise around the wall and the weft upright. The fabric has a strength-to-weight ratio and stretch characteristic sufficient that the wall requires no internal reinforcement or external support against outward pressure from contents when filled into the container.