Patent ID: 11932960
Assignee: ARIZONA BOARD OF REGENTS ON BEHALF OF ARIZONA STATE UNIVERSITY
Field: Surface technology, coating (Chemistry)
Classification: CPC C  H | IPC C  H

Claim 14:
15. A method for processing a silicon solar cell, the method comprising:
preparing an ionic liquid comprising aluminum chloride (AlCl3) and 1-ethyl-3-methylimidazolium tetrachloraluminate (EMIm-AlCl4);
patterning a partially-processed silicon solar cell to expose an n-type surface of a silicon substrate;
cleaning the n-type surface with at least one of hydrogen fluoride, hydrogen chloride, hydrogen peroxide, sodium hydroxide, potassium hydroxide, or ammonium hydroxide;
bringing the n-type surface into contact with the ionic liquid, wherein the n-type surface does not comprise a seed layer;
illuminating the n-type surface, wherein the illumination passes through the ionic liquid and wherein the illumination is generated at least partially by a light source comprising at least one light-emitting diode with a wavelength of about 620 nanometers, and a photo-generated current is generated by the illumination;
while illuminating the silicon substrate with the light source, applying a current between an anode and a cathode to generate an applied current, wherein the applied current generates a current density of between 30 mA/cm2 and 50 mA/cm2;
depositing aluminum onto the silicon substrate via a light-induced electroplating process, wherein the light-induced electroplating process comprises applying a current between an aluminum back electrode of the partially-processed silicon solar cell and an aluminum mesh disposed in the ionic liquid, and wherein the light-induced electroplating process utilizes the applied current that does not exceed the photo-generated current generated by the illumination;
cleaning the deposited aluminum with deionized water; and
annealing the deposited aluminum on the silicon substrate to reduce the resistivity of the electroplated aluminum.