Accession Number : ADA254326


Title :   Investigation of High Efficiency Monolithic Multibandgap Solar Cells


Descriptive Note : Final rept. 15 Nov 1990-15 Nov 1991,


Corporate Author : WASHINGTON UNIV SEATTLE


Personal Author(s) : Olsen, Larry


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a254326.pdf


Report Date : 15 Nov 1991


Pagination or Media Count : 26


Abstract : This program involved investigations of A1GaAs/GaAs multijunction solar cells. Most of the low level effort was devoted to studies of the electronic properties of A1GaAs films. Finite diffusion lengths could only be obtained for A1(x)Ga(1-x)As films with the aluminum concentration in the range from 0 to 0.1. Photoresponse of A1/A1GaAs Schottky barriers were anlayzed to measure minority carrier diffusion length (L). Values of L for p-type A1GaAs with x=0 were typically in the range of 0 to 0.5 micron. It is clear that much more effort must be made to reduce oxygen and water impurity levels in the WSU barrel-type reactor before improved A1GaA Schottky barriers is explained as being due to improper mixing of A1 and Ga precursors. Results are discussed for films grown with improved mixing which do not exhibit the apparent bandgap shift. Estimated performance for a two-cell, A1GaAs/GaAs structure are given based on characteristics of A1(.37)Ga(.63)As cells fabricated from wafers obtained from Varian, and GaAs cells fabricated for epi wafers grown with the WSU reactor.


Descriptors :   *THIN FILMS , *SEMICONDUCTORS , *SOLAR CELLS , ELECTRONICS , ALUMINUM ALLOYS , WATER , FILMS , ALUMINUM , BARRIERS , BARRELS , SCHOTTKY BARRIER DEVICES , WAFERS , VALUE , DIFFUSION , MIXING , LOW LEVEL , LENGTH , OXYGEN , IMPURITIES , EFFICIENCY , PRECURSORS , GALLIUM ARSENIDES , MINORITIES


Subject Categories : Electrical and Electronic Equipment
      Electric Power Production and Distribution


Distribution Statement : APPROVED FOR PUBLIC RELEASE