Oxygen-layer structure improves lithium-doped silicon solar cells

Technique fabricates hybrid structure utilizing low oxygen silicon as bulk cell material and shallow overlay of silicon with high oxygen concentration

Posterior fossa craniectomy and C1/C2 laminectomy for Arnold-Chiari II decompression of syrinx

This patient was diagnosed shortly after birth with right-sided facial palsy as a result of lower motor neuron facial nerve involvement, together with spinal abnormalities and hearing impairment (patient currently uses hearing aids). He also has 13 ribs on his left side and 11 ribs on the right, hemi-vertebra at T2/T3 and T8/T9 and fused vertebral bodies at C2/C3 and C6/C7. As a result, clinically he has a short neck with restriction of all neck movements, particularly rotation. Patient is also known to have situs inversus. From the MRI, it showed he had an Arnold-Chiari malformation. Therefore, the cerebellar tonsils herniated through the foramen magnum which resulted in disruption of the CSF flow. This lead to the formation of a syrinx within the spinal cord, the condition being known as Syringomyelia. The syrinx can expand and elongate over time, destroying part of the spinal cord so that the damage will cause the symptoms felt by the patient. Symptoms vary between patients and also depending on the location of the syrinx; in this case, the patient experienced the gait disturbances, balance problems, paraesthesia, pain and bowel control issues. His symptoms suggest a cape-like distribution of paraesthesia and sensory disturbance attributable to syringomyelia.peer-reviewe

Research, development and pilot production of high output thin silicon solar cells

Work was performed to define and apply processes which could lead to high output from thin (2-8 mils) silicon solar cells. The overall problems are outlined, and two satisfactory process sequences were developed. These sequences led to good output cells in the thickness range to just below 4 mils; although the initial contract scope was reduced, one of these sequences proved capable of operating beyond a pilot line level, to yield good quality 4-6 mil cells of high output

Study of Lithium Doped Solar Cells Quarterly Report

Study of lithium doped solar cell

Metallization problems with concentrator cells

Cells used with concentrators have similar contact requirements to other cells, but operation at high intensity imposes more than the usual demands on the metallization. Overall contact requirements are listed and concentrator cell requirements are discussed

Some disconnected speculations on slicing silicon

The basic principles for qualifying silicon wafering methods are summarized, and unconventional methods of wafering was discussed. Methods of cleaving analogous to diamond cutting, geological processes employing the expansion of freezing water, and karate chops are touched upon

Study of lithium doped solar cells

Solar cell properties change from lithium dopin

Development and fabrication of lithium-doped solar cells

The application of contacts and coatings after lithium diffusion provides good electrical output and satisfactory contact adhesion by sintering for short times at temperatures less than the lithium diffusion temperature. High output and repeatability are obtainable from both oxygen-rich and oxygen-lean silicon. These fabrication sequence alterations have led to higher cell output, better appearance, and increased contact strength

Research, Development and Fabrication of Lithium Solar Cells

This report continues studies on cells made with low temperature (<400degC) single-cycle, lithium diffusion schedules. Measurements of concentration of lithium at the back surface showed that C(sub S) changes with time consisting of a build-up to a maximum value (above 10(exp 17) cm(exp -3)) with gradual decrease at longer diffusion times. Using the estimated C(sub S) values, theoretical lithium profiles were calculated. The calculated concentration near the PN junction was higher than those measured by the capacitance voltage (C-V) technique. The calculated concentration gradients were one-seventh of those measured by C-V methods. Both the concentration and its gradient were proportional to C(sub S). Estimates of C(sub S) obtained by extrapolating from C-V measured values of concentration and gradient near the PN junction, showed a decrease in C(sub S) for longer diffusion times. This fact supported the trend observed in Shipment C-13, where,, at longer times, the spread in values of V(sub oc), lithium concentration, and gradient became greater. The general conclusion was that the I-V characteristics were well controlled, with good cell output, but for longer diffusion times the lithium concentration gradient could have wider spread. The work described has led to greater insight into the lithium distribution dependence on the surface conditions. The surface conditions could be changed by varying the method used to apply lithium. Vacuum evaporation of lithium shows promise, and another exhaustive test of this method is in progress. Shipment C-13 is summarized, and the succeeding lots (C-14, C-15) are described. It is felt that improved monitoring of cell properties is at hand, and that the control of cell fabrication processes has advanced to where the effects of subtle differences in lithium distribution can now be seen. Evaluation is continuing on the best method to scale up the fabrication steps. A different sequence of fabrication is planned for Shipments C-14 and C-15

Study of lithium doped solar cells Final report

Improved cell stability in charged particle environment of space by using lithiu