Growth and Properties of ZnO:Al on Textured Glass for Thin Film Solar Cells

Abstract

Aluminium induced texturing (AIT) method has been used to texture glass substrates in order to enhance the photon absorption in thin film solar cells. The resultant glass roughness has been analyzed by varying the AIT process parameters and it has been found that the deposition method of Al is a decisive factor in tuning the texture. Two types of textures, a soft (texture E) and a rough texture (texture S), were achieved from the thermally evaporated and sputtered Al layers through AIT process. Aluminium-doped zinc oxide (AZO) layers of different thickness were deposited over both textures and over smooth glass. Haze values above 30% were obtained for texture S + AZO and above 10% for texture E + AZO. The resultant morphologies were free from sharp edges or deep valleys and the transparency and the resistivity values were also good enough to be used as front contact for thin film solar cells. In order to demonstrate the light absorption enhancement in a solar cell device, 200 nm of a-Si:H followed by 300 nm of Ag were grown over the textured and smooth substrates with AZO, and an optical absorption enhancement of 35% for texture E and 53% for texture S was obtained in comparison to the smooth substrate.

Chemical Solution Deposition of Al(OH)3‐AlOOH Films: Application for Surface Sensitizing of Rigid and Flexible Substrates to Improve the Adhesion in Coating Technology Areas

“…However, scattering surfaces are advantageous in some cases: if the light strikes the glass side instead of the Al(OH) 3 -AlOOH side, the light reaches later the Al(OH) 3 -AlOOH material, travels through this material, and at the moment of leaving this material the light is scattered in different directions, thus being homogeneously distributed in the bulk of the following material, such as, for example, the subsequent CdS material that will be deposited on it (this is similar to what occurs inside the spectrophotometer, with the difference that in this case the dispersed light is captured by other material deposited on the Al(OH) 3 -AlOOH thin film instead of being captured by the black covering inside the equipment). In fact, there are some reports that deal with methodologies for texturing glass surfaces in order to induce some scattering degree to enhance light trapping in the next deposited material, [36][37][38][39] which is advantageous in solar cells technology.…”

Influence of coevaporation process on CIGS solar cells with reduced absorber thickness and current enhancement with periodically textured glass substrates

“…Sheet resistance of the back electrode on flat reference substrate is 0.33 Ω.□ −1 while values between 0.70 Ω.□ −1 and 1.60 Ω.□ − 1 have been measured for S-0.5, S-1.0 and S-2.5. Texturation also implies an increased roughness for ZnO:Al deposition which leads to a higher sheet resistance in this layer [20].…”

Aluminum induced texturing of sandy and prism glasses: Combination of micro/nano texture with macro texture

“…Light management in thin film solar cells is important in order to increase the optical path of light in highly defective absorber layers . In this manner, it can be particularly used in further reducing the absorber thicknesses in rare material (i.e., Cd, Te, Ga, etc.)…”