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Title: Increased Optoelectronic Quality and Uniformity of Hydrogenated p-InP Thin Films

The thin-film vapor–liquid–solid (TF-VLS) growth technique presents a promising route for high quality, scalable, and cost-effective InP thin films for optoelectronic devices. Toward this goal, careful optimization of material properties and device performance is of utmost interest. Here, we show that exposure of polycrystalline Zn-doped TF-VLS InP to a hydrogen plasma (in the following referred to as hydrogenation) results in improved optoelectronic quality as well as lateral optoelectronic uniformity. A combination of low temperature photoluminescence and transient photocurrent spectroscopy was used to analyze the energy position and relative density of defect states before and after hydrogenation. Notably, hydrogenation reduces the relative intragap defect density by 1 order of magnitude. As a metric to monitor lateral optoelectronic uniformity of polycrystalline TF-VLS InP, photoluminescence and electron beam induced current mapping reveal homogenization of the grain versus grain boundary upon hydrogenation. At the device level, we measured more than 260 TF-VLS InP solar cells before and after hydrogenation to verify the improved optoelectronic properties. Hydrogenation increased the average open-circuit voltage (V OC) of individual TF-VLS InP solar cells by up to 130 mV and reduced the variance in V OC for the analyzed devices.
Authors:
 [1] ;  [2] ;  [2] ;  [2] ;  [2] ;  [1] ;  [3] ;  [3] ;  [3] ;  [3] ;  [4] ;  [4] ;  [5] ;  [6] ;  [6] ;  [7] ;  [2]
  1. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); King Abdullah Univ. of Science & Technology (KAUST), Thuwal (Saudi Arabia); National Taiwan Univ., Taipei (Taiwan)
  2. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  3. Univ. of Oregon, Eugene, OR (United States)
  4. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  5. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  6. Univ. of California, Berkeley, CA (United States)
  7. King Abdullah Univ. of Science & Technology (KAUST), Thuwal (Saudi Arabia)
Publication Date:
Grant/Contract Number:
AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 28; Journal Issue: 13; Journal ID: ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE
OSTI Identifier:
1393059