Axial p-n junction design and characterization for InP nanowire array solar cells

Qian Gao, Ziyuan Li, Li Li, Kaushal Vora, Zhe Li, Ahmed Alabadla, Fan Wang, Yanan Guo, Kun Peng, Yesaya C. Wenas, Sudha Mokkapati, Fouad Karouta, Hark Hoe Tan, Chennupati Jagadish, Lan Fu

Research output: Contribution to journalArticleResearchpeer-review

14 Citations (Scopus)


In this work, InP nanowire (NW) array solar cells with different axial p-i-n junction designs were investigated. The optical properties of the different NW structures were characterized through a series of microphotoluminescence measurements to extract important material parameters such as minority carrier lifetimes and internal quantum efficiencies. A glancing angle sputtering deposition technique has been developed to enable a direct visualization of the p-n junctions in the vertical array of InP NW solar cells (NWSCs) using electron beam-induced current (EBIC) technique. Based on EBIC and electrical simulation, it is found that the background doping in NWSC significantly affects the junction position. By modifying the junction design, the width and position of the p-n junction can be varied effectively. By employing a p-p -n structure, a high junction position (>1 μm from the substrate) and wide depletion width have been achieved as confirmed by EBIC measurement. Moreover, the NW growth substrate does not show any influence on the device behavior due to the fully decoupled junction position, indicating a promising structural design for future development of high-performance, low-cost flexible NW devices.

Original languageEnglish
Pages (from-to)237-244
Number of pages8
JournalProgress in Photovoltaics: Research and Applications
Issue number3
Publication statusPublished - 20 Feb 2019
Externally publishedYes


  • axial junction
  • EBIC
  • electroluminescence
  • III-V compound semiconductors
  • nanowire array solar cells
  • selective-area MOVPE

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