Abstract
This report describes the significant progress made in four areas of this subcontract: process and equipment development; efficiency improvement; characterization and analysis; and environmental, health, and safety. As part of the process and equipment development effort, vapor-transport deposition (VTD) was implemented first on a 60-cm-web pilot-production system, then on a 120-cm-webhigh-throughput coater. Deposition of CdS and CdTe films at a throughput of 3 m2/min was demonstrated, and more than 56,000 plates (each 0.72 m2) were coated -- 16 times the total number coated prior to the start of the contract. Progress was also made in the conversion efficiency and yield of both standard and next-generation modules, with data from more than 3000 sequentially deposited moduleshaving an average total-area conversion efficiency of 7% and next-generation modules produced with efficiency as high as 9.3% (10.15% aperture-area efficiency as measured by NREL). Successful implementation of in-situ CdS thickness measurements was important to progress in thickness uniformity and control. Net CdTe material utilization of 82% was demonstrated. The ability to raise theutilization further was shown with the demonstration of inherent CdS and CdTe material utilizations of over 90%. Post-CdTe-deposition process development, which included process space exploration and problem diagnosis, was an important part of advances in efficiency and yield. As part of the efficiency-improvement task, research was done on cells and modules with reduced CdS thickness toincrease photocurrent.
Original language | American English |
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Number of pages | 47 |
State | Published - 2002 |
Bibliographical note
Work performed by First Solar Technology Center, Perrysburg, OhioNREL Publication Number
- NREL/SR-520-32041
Keywords
- back contacts
- coater durability
- electron-beam induced current (EBIC)
- finite difference
- interfacial layer
- light emitting diodes
- open-circuit voltages
- photoluminescence
- PV
- recrystallization
- semiconductor film thickness
- vapor transport deposition (VTD)