High haze transparent contact including ion-beam treated layer for solar cells, and/or method of making the same
Certain example embodiments of this invention relate to a front transparent conductive electrode for solar cell devices (e.g., amorphous silicon or a-Si solar cell devices), and/or methods of making the same. Advantageously, certain example embodiments enable high haze to be realized in the top layer of the thin film stack. In certain example embodiments, an insertion layer comprising ITO or AZO is provided between a layer of AZO and a layer of ITO. The AZO may be deposited at room temperature. The insertion layer is provided with an oxygen content selected so that the insertion layer sufficient to alter the crystalline growth of the layer of AZO compared to a situation where no insertion layer is provided. In certain example embodiments, the layer of ITO may be ion-beam treated so as to roughen a surface thereof. The ion beam treating may be performed a voltage sufficient to alter the crystalline growth of the layer of AZO compared to a situation where no insertion layer is provided.
1 . A method of making a front contact for a solar cell, the method comprising:
providing a glass substrate;
disposing a dielectric coating on the glass substrate;
disposing a layer of ITO on the dielectric coating;
treating the layer of ITO with an ion beam to roughen a surface thereof;
sputter-depositing a layer of AZO on the layer of ITO, the layer of AZO being sputter-deposited at a temperature less than 200 degrees C.;
etching the layer of AZO; and
baking and/or heat treating the substrate together with the dielectric coating, the layer of ITO, and the layer of AZO.
2 . The method of claim 1 , wherein the temperature at which the layer of AZO is sputter-deposited is about room temperature.
3 . The method of claim 1 , wherein the etching comprises etching with an acetic acid solution.
4 . The method of claim 1 , wherein the etching is performed before the baking and/or heat treating.
5 . The method of claim 1 , wherein the etching is performed after the baking and/or heat treating.
6 . The method of claim 1 , wherein the dielectric coating comprises titanium oxide and/or silicon oxide.
7 . The method of claim 6 , wherein the dielectric coating comprises silicon oxynitride.
8 . The method of claim 1 , wherein the ion beam treating alters the crystalline growth of the layer of AZO compared to a situation where no ion beam treating is performed.
9 . The method of claim 8 , wherein the ion beam treating causes the 002 peak of the layer of AZO to shift compared to a situation where no ion beam treating is performed.
10 . The method of claim 1 , wherein the layer of ITO is graded such that there is more oxygen closer to the AZO and less oxygen closer to the dielectric coating.
11 . The method of claim 1 , wherein the layer of AZO is graded such that there is more oxygen closer to the AZO and less oxygen closer to the dielectric coating.
12 . The method of claim 1 , wherein voltage associated with the ion beam treating is greater than 500 V.
13 . The method of claim 1 , wherein the ion beam uses Ar and/or oxygen.
14 . The method of claim 1 , further comprising providing a layer of Ag above and/or below the ITO.
15 . A method of making a solar cell, the method comprising:
connecting the front contact of claim 1 to an a-Si semiconductor layer.
16 . A method of making a front contact for a solar cell, the method comprising:
providing a glass substrate;
sputter-depositing a dielectric coating on the glass substrate;
sputter-depositing a layer of ITO on the dielectric coating;
treating the layer of ITO with an ion beam to roughen a surface thereof, the ion beam treating being performed at a voltage greater than 500 V; and
sputter-depositing a layer of AZO on the layer of ITO,
wherein the ion beam treating alters the crystalline growth of the layer of AZO compared to a situation where no ion beam treating is performed.
17 . A method of making a solar cell, the method comprising:
connecting the front contact of claim 16 to an a-Si semiconductor layer.
18 . A front contact for a solar cell, comprising:
a glass substrate;
a dielectric coating disposed on the glass substrate;
a layer of ITO disposed on the dielectric coating; and
a layer of AZO sputter-deposited on the layer of ITO at a temperature less than 200 degrees C.;
wherein the layer of AZO is etched,
wherein the substrate is baked and/or heat treated together with the dielectric coating, the layer of ITO, and the layer of AZO, and
wherein the layer of ITO is ion-beam treated to roughen a surface thereof.
19 . The front contact of claim 18 , wherein the temperature at which the layer of AZO is sputter-deposited is about room temperature.
20 . The front contact of claim 18 , wherein the dielectric coating comprises titanium oxide and/or silicon oxide.
21 . The method of claim 20 , wherein the ion beam treatment is performed at a voltage sufficient to alter the crystalline growth of the layer of AZO compared to a situation where no ion beam treating is performed.
22 . A solar cell, comprising:
a front contact according to claim 18 ; and
an a-Si semiconductor layer.
23 . A front contact for a solar cell, comprising:
a glass substrate;
a sputter-deposited dielectric coating on the glass substrate;
a sputter-deposited layer of ITO on the dielectric coating, wherein the ITO is ion beam treated to roughen a surface thereof; and
a sputter-deposited layer of AZO on the layer of ITO,
wherein the ion beam treating being performed at a voltage sufficient to alter the crystalline growth of the layer of AZO compared to a situation where no insertion layer is provided.
24 . A solar cell, comprising:
a front contact according to claim 23 ; and
an a-Si semiconductor layer.