Fabrication of Single GaAs Solar Cell by MBE

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Discussion Overview

The discussion centers around the fabrication of a single junction GaAs solar cell using Molecular Beam Epitaxy (MBE) techniques. Participants explore various aspects of the fabrication process, including contact layer connections, material properties, and measurement techniques.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • Jayko seeks advice on how to connect the bottom contact layer with the top electrode layer to achieve maximum current for I-V characteristic measurements.
  • Some participants inquire whether the solar cell is a multi-junction cell and clarify that it is a single junction with GaAs (100) as the substrate.
  • There is a suggestion to minimize contact resistance, with a recommendation to make separate contacts to both the front and back layers.
  • Jayko mentions testing materials and thicknesses to achieve a contact resistance of a few ohms and discusses the challenges of aligning the anti-reflective (AR) coating mask with the grid mask.
  • A question is raised about the toxicity of arsenic (As), which is relevant to the materials used in the solar cell fabrication.

Areas of Agreement / Disagreement

Participants express varying viewpoints on the best methods to connect layers and minimize contact resistance, indicating that there is no consensus on a single approach. The discussion remains unresolved regarding the optimal techniques and configurations for the solar cell fabrication.

Contextual Notes

Participants have not finalized the dopant concentration or layer thickness, and there are unresolved issues related to the alignment of the AR coating mask.

JayKo
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Fabrication of Single Junction GaAs Solar Cell by MBE

Hi All,

My project is to produce 1 single piece of GaAs solar cell (about the size of 1cm square) by MBE technique. I have gone through some read up and simulation software software called atlas by silvaco. for time being, I am testing on other sample to do the thermal evaporation and photo lithography. how ever my question is.

how do i connect the bottom contact layer with the top electrode layer so as to achieve maximum current for my I V characteristic measurement.

I have some very rough sample shown in the picture below, and I try to search through the net but to no avail. I would be most grateful if you guys could give me some valuable inputs.
thanks
Jayko
http://img137.imageshack.us/img137/4448/solarcell.jpg

Uploaded with ImageShack.us

The 2 fine wires on top is the gold wires (cathode) the bottom is connected to copper foil (anode)
 
Last edited by a moderator:
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It this a multi-junction cell? Is the substrate also GaAs, or something else? Can you draw a simple schematic of the device geometry?
 
Gokul43201 said:
It this a multi-junction cell? Is the substrate also GaAs, or something else? Can you draw a simple schematic of the device geometry?

sorry for the incomplete info.
is a single junction with GaAs (100) as substrate
here is the picture.
as for the dopant concentration, and layers thickness. it is still yet to finalize, as I'm still working on dummy sample set. thanks.

http://img819.imageshack.us/img819/1641/76048936.jpg

Uploaded with ImageShack.us
 
Last edited by a moderator:
you need to minimize the contact resistance. you might make separate contacts to both front and back and keep trying until your contact resistance is few ohms. is there AR coating on the small wires, or do you need to solder to the bigger bus bar.
 
Hi Kevin75081,

Thanks, so the point is to trying out the materials and thickness to have a contact resistance of few ohms? I will first do without AR coating and measure the contact resistance. right now the contact to the bus bar is by soldering to a 0.02 diameter gold wire.

without the AR coating is because I have yet to final the method to align the AR coating mask with the grid mask.
 


JayKo said:
Hi All,

My project is to produce 1 single piece of GaAs solar cell (about the size of 1cm square) by MBE technique. I have gone through some read up and simulation software software called atlas by silvaco. for time being, I am testing on other sample to do the thermal evaporation and photo lithography. how ever my question is.

how do i connect the bottom contact layer with the top electrode layer so as to achieve maximum current for my I V characteristic measurement.

I have some very rough sample shown in the picture below, and I try to search through the net but to no avail. I would be most grateful if you guys could give me some valuable inputs.
thanks
Jayko
http://img137.imageshack.us/img137/4448/solarcell.jpg

Uploaded with ImageShack.us

The 2 fine wires on top is the gold wires (cathode) the bottom is connected to copper foil (anode)

Is As toxic?
 
Last edited by a moderator:

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