[labnetwork] Cross contamination due to evaporation on lead containing perovskite material

[Noah Clay]

Hi Aamer,

It’s a tough situation when you have to put a material in a chamber that makes you uneasy and could affect other researchers’ work in your lab.  If it must be done, I recommend avoiding ion pre-cleans, substrate bias, heating or other wafer-level processes that might volatilize Pb from the perovskites.  Here’s my two cents, FWIW:

1. Benchmark your chamber: deposit a film such as silver on a bare wafer, which entrains background contamination and can be used in SIMS or XPS analysis to fingerprint the current chamber state.

2. Protect the chamber: UHV foil wrap appropriate inner chamber hardware.  Run the process and tear down the foil.

3. Compare chamber states: Repeat #1 and quantify any deltas.

Good luck,
Noah Clay

University of Pennsylvania 
Philadelphia, PA

Sent from my iPhone

> On Nov 10, 2019, at 08:57, Dr. Aamer Mahmood <amahmood at hbku.edu.qa> wrote:
> 
> 
> Hello all,
> I have been asked by a colleague to evaporate gold on some organic photovoltaic cells. The cells contain lead containing perovskite material.
> The evaporator used traditionally for perovskite based research is currently down and to save time the use of another evaporator used for evaporation of metals and reactively deposited metal oxides is being explored.
> I am concerned about contamination of the chamber – especially by lead.
> I would appreciate relevant experiences and opinions.
> Thanks.
> -Aamer Mahmood
>  
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