N-GaAs/PEDOT:PSS 混和式太陽能電池中的接面形成與傳輸機制

Abstract

近年來，混和型太陽能電池結合了有機高分子及無機半導體材料，因其較為簡單、不需經高溫的製程且可降低製程成本而受到學者們的關注。本論文藉由改變砷化鎵基板的摻雜濃度，研究n-GaAs/PEDOT:PSS 混和型太陽能電池的接面特性。 我們量測使用不同摻雜濃度砷化鎵基板所製成元件的光電流、暗飽和電流及內建電場，以及利用紫外光電子能譜儀量測高分子的價帶邊緣及功函數，建構出n-GaAs/EDOT:PSS混和式接面的能階圖，且分別用PN接面與蕭特基接面模型去分析元件的電流-電壓特性，從數據中發現到其電流傳輸是由多數載子的熱離子放射所主導，推測其n-GaAs與PEDOT:PSS之間的接面應屬於蕭特基接面。

In recent years the combination of inorganic semiconductor and organic polymer materials, usually named hybrid, has attracted a lot of attention due to simple and low temperature fabrication processes with relatively inexpensive cost. In this study, we investigated the interface junction formation properties of n-GaAs/PEDOT:PSS hybrid solar cells on planar substrates by varying the GaAs substrates doping concentrations. The photocurrent, dark saturation current and build-in potential at this hybrid interface are measured by varying n-GaAs doping concentrations. The work function and valence band edge of the polymer are extracted from ultraviolet photoelectron spectroscopy to construct the band diagram of the hybrid n-GaAs/PEDOT:PSS junction. The current-voltage characteristics were analyzed by using pn-junction and Schottky models. The experimental evidences suggested that the interface between n-GaAs and PEDOT:PSS is most likely a Schottky type junction and the current transport is governed by thermionic emission of majority carriers over a barrier.