Abstract: By using an improved back reflecting layer, a photovoltaic cell having excellent migration resistance and a high photoelectric conversion efficiency is provided at high productivity. The photovoltaic cell includes a metal layer comprising a silver-aluminum alloy having a content of silver equal to or less than 30 atomic percent, the rest being aluminum, or a metal layer comprising a copper-aluminum alloy having a content of copper between 30 and 50 atomic percent, the rest being aluminum. It is preferable to form these layers at a relatively low temperature by sputtering, particularly at a temperature equal to or less than 110.degree. C. for the silver-aluminum alloy and at a temperature equal to or less than 120.degree. C. for the copper-aluminum alloy.

Abstract: A method for making a photovoltaic device includes the steps of: (a) forming a transparent conductive layer on a substrate, (b) putting the surface of the transparent conductive layer into contact with an ionized inert gas, and (c) forming a semiconductor layer thereon. The transparent conductive layer is formed such that in the cross-section of the transparent conductive layer, a mean distance between relative minimum points is 2,000 nm or less and a mean tilt angle between a surface line originated from a measuring point and a base line connecting to the nearest two adjacent relative minimum points over the entire measured region is 5.degree. or more.

Abstract: An optical module includes support substrate, an optical waveguide on the support substrate, a photoreception device on the support substrate, an optical path conversion part for converting an optical path of an optical beam guided through the optical waveguide from a first optical path to a second optical path that leads to a photodetection area of said photoreception device, wherein the optical path conversion part is provided on the photodetection device as a part thereof, such that the optical beam emitted from the optical waveguide impinges upon the photodetection area of the photoreception device.

Abstract: A process for making high-efficiency solar cells. This is accomplished by forming a diffusion junction and a passivating oxide layer in a single high-temperature process step. The invention includes the class of solar cells made using this process, including high-efficiency solar cells made using Czochralski-grown silicon.

Abstract: An improved solar cell design and method of fabrication that primarily uses two materials, n-type doped silicon and aluminum to form a p-n alloy junction back contact solar cell. The aluminum alloy junctions are placed on the back (unilluminated) side of the cell, thereby combining the desirable features of aluminum (as a dopant, contact metal and light reflector), with the advantages of a back contact cell. The cell design and method of fabrication includes such features as surface texturing, front and back surface field minority carrier mirrors, surface passivation using oxidation layers, use of Al contacts as light reflectors, intrinsic protection against reverse bias due to contiguous n.sup.+ and p.sup.+ regions, and an improved bus bar contact design suitable for interconnecting cells using a surface mount technology. An improved method of ohmic contact formation uses a self-alignment technique for forming the ohmic contacts.