The converter obtains an efficient conversion of solar electromagnetic radiation into electrical power. A p-n junction is fabricated close to an optical surface of a region of n-type GaAs which is receptive of the solar radiation. There is a window on the optical surface consisting of a window layer of Ga.sub.1.sub.-x Al.sub.x As, where x is less than one and greater than zero with a composition to cause the window layer to contribute selectively to absorbing and transmitting certain components of the incoming solar radiation. The layer of Ga.sub.1.sub.- x Al.sub.x As is made nearly transparent to electromagnetic radiation and is nearly absorbent of the energetic particle radiation content of the received solar radiation. The window layer is an integral part of the procedure for forming the p-n junction. It contributes the p-type doping species to the junction by diffusion into the n-type GaAs substrate. For certain applications, the Ga.sub.1.sub.-x Al.sub.x As window can be removed by etching with aqueous solution of HCl. If the window is removed, the ohmic contact is then made to the optical surface of the p-type GaAs. Illustratively, another structure provided by this disclosure includes a window of GaP of p-type conductivity on the surface of a region of n-type InP with a p-type transition region of InP therebetween.
Gallium phosphide single crystals with low defect density which are manufactured by the liquid encapsulation Czochralski pulling method and which are characterized in that they are doped or not doped with at least one kind of dopant which is electrically active in gallium phosphide and are so doped as to have at least one dopant such as boron or some other strongly reducing impurity which has a reducing activity equal to or greater than that of boron remain in the crystals in a quantity not less than 1.times.10.sup.17 cm.sup.-3 and the sum of dislocation etch pit density and small conical etch pit density of the surface (111)B which has been subjected to etching for 3 to 5 minutes with RC etchant at a temperature of 65.degree. C..about.75.degree. C. after removing the mechanically damaged layer on the surface does not exceed 1.times.10.sup.5 cm.sup.-2, and a method of manufacturing the crystals.
A technique for fabricating a semiconductor heterostructure by growth of a ternary semiconductor on a binary semiconductor substrate from a melt of the ternary semiconductor containing less than saturation of at least one common ingredient of both the binary and ternary semiconductors wherein in a single temperature step the binary semiconductor substrate is etched, a p-n junction with specific device characteristics is produced in the binary semiconductor substrate by diffusion of a dopant from the melt and a region of the ternary semiconductor of precise conductivity type and thickness is grown by virtue of a change in the melt characteristics when the etched binary semiconductor enters the melt.
A technique for fabricating a semiconductor heterostructure by growth of a ternary semiconductor on a binary semiconductor substrate from a melt of the ternary semiconductor containing less than saturation of at least one common ingredient of both the binary and ternary semiconductors wherein in a single temperature step the binary semiconductor substrate is etched, a p-n junction with specific device characteristics is produced in the binary semiconductor substrate by diffusion of a dopant from the melt and a region of the ternary semiconductor of precise conductivity type and thickness is grown by virtue of a change in the melt characteristics when the etched binary semiconductor enters the melt.
Due to its dopant structure, the radiant band of a III(A) - V(B) type luminescent diode, emitting light radiation in the plane of the PN-junction, possesses differences in delay time of .ltoreq. 10.sup.-10 seconds, which permit an extension to higher frequencies. The dopant structure is characterized by an n.sup.+ type basic material incorporating an impurity concentration of N.sub.D .gtoreq. 10.sup.18 cm.sup.-3, and by a graded acceptor dopant profile which within the radiant region has a gradient of .ltoreq. 10.sup.22 cm.sup.-4 and a gradient of .gtoreq. 10.sup.23 cm.sup.-4 in the vicinity of the p.sup.+ region. Thus the injection conditions in respect to the quantum efficiencies and to the frequency range are improved. The diode is fabricated by a diffusion process and/or a liquid epitaxial process, in which definite temperatures and time relations have to be satisfied.
An X-ray receptor for producing electrical signals representative of an X-ray image. An array of semiconductor elements is mounted on at least one support, each element being formed of semiconductor material which is (1) an element of Group 4A of the Periodic Table of Elements or a compound of such an element, or which is (2) at least one element of Group 3A of the Periodic Table of Elements together with at least one element of Group 5A of the Periodic Table of Elements, and having at least one PN junction therein. The array is positioned to receive impinging X-rays and to produce electrical signals in response thereto. Electrical conducting leads are supported on the support, and the electrical signals which are produced by respective ones of the semiconductor elements are coupled to these electrical conducting leads. Output terminals also are supported on the support to provide output image signals; and circuitry including multiplexing circuits additionally is supported on the support for processing and multiplexing the electrical signals from the electrical conducting leads to the output terminals. Also disclosed is a method by which the X-ray receptor is made.
