Novel light trapping scheme for thin crystalline cells utilizing deep structures on both wafer sides
- Technical Univ. of Denmark, Lyngby (Denmark). Microelectronics Centre
A new light trapping structure is presented with trapping capabilities comparable to or better than those of the perpendicular grooves structure. The new structure traps a larger fraction of rays for 8--80 passes than the perpendicular grooves structure. The average path length enhancement is about 62 times the average thickness. The structure consists of deep ({approximately}200 {micro}m) inverted pyramids on the front side and deep ({approximately}200 {micro}m) truncated pyramids with eight sides on the back. The structure is realized in crystalline silicon by wet chemical etching using potassium hydroxide (KOH) and isopropanol (IPA). A process for creating thin solar cells with this light trapping scheme is described. The process includes only two main photolithographic steps and features a self aligned front metallization. The process uses 250 {micro}m wafers to create cells that on average are about 70 {micro}m thick.
- OSTI ID:
- 302485
- Report Number(s):
- CONF-970953--
- Country of Publication:
- United States
- Language:
- English
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