HIGH EFFICIENCY Cu(ln,Ga)SepBASED SOLAR CELLS: PROCESSING OF NOVEL ABSORBER STRUCTURES

Our effort towards the attainment of high performance devices has yielded several devices with total-area conversion efficiencies above 16%, the highest measuring 16.8% under standard reporting conditions (ASTM E892-87, Global 1000 W/m’). The first attempts to translate this development to larger areas resulted in an efficiency of 12.5% for a 16.8~cm2 monolithically interconnected submodule test structure, and 15.3% for a 4.85-cm* single cell. Achievement of a 17.2% device efficiency fabricated for operation under concentration (22-sun) is also reported. All high efficiency devices reported here are made from graded bandgap absorbers. Bandgap grading is achieved by compositional Ga/(ln+Ga) profiling as a function of depth. The fabrication schemes to achieve the graded absorbers, the window materials and contacting will be described.