Optoelectric Properties of GaInP p-i-n Solar Cells with Different i-Layer Thicknesses

Tsung-Shine Ko,You-Chi He,Fan-Lei Wu,Bo-Yuan Hu,Der-Yuh Lin,Chih-Hung Wu,Chen-Chia Kao,Yu-Li Tsai,Ray-Hua Horng

doi:10.1155/2015/703045

Abstract

The optoelectric properties of GaInP p-i-n solar cells with different intrinsic layer (i-layer) thicknesses from 0.25 to 1 μm were studied. Both emission intensity and full width at half maximum features of the photoluminescence spectrum indicate that the optimum i-layer thickness would be between 0.5 and 0.75 μm. The integrated current results of photocurrent experiment also point out that the samples with 0.5 to 0.75 μm i-layer thicknesses have optimum value around 156 nA. Electroreflectance measurements reveal that the built-in electric field strength of the sample gradually deviates from the theoretical value larger when i-layer thickness of the sample is thicker than 0.75 μm.I-Vmeasurements also confirm crystal quality for whole samples by obtaining the information about short currents of photovoltaic performances. A series of experiments reflect that thicker i-layer structure would induce more defects generation lowering crystal quality.

Highlights

Solar cell devices play an important role in renewable energies which convert solar energy directly into electricity
It is well known that the built-in electric field plays a critical role in solar cell devices; it is difficult to detect by electric methods directly and less studies have been reported [3]
Comparing with the PL peak intensity of samples A, B, and C, the intensity of sample D is quite small. This weak PL intensity indicates that the i-layer quality is not good due to many defects that have been generated in sample D, which affects the efficiency of the solar cell

Summary

Introduction

Solar cell devices play an important role in renewable energies which convert solar energy directly into electricity. The high cost of III-V tandem cells has been the main impediment for their widespread applications Another kind of basic solar cell structures is p-i-n structure, which consists of p- and n-doped regions on top and bottom layers and an intrinsic layer (i-layer) in middle one. In order to evaluate the i-layer quality, a systematic optical characterization of thickness and built-in electric field must be clarified for giving us information in order to optimize the power conversion efficiency. These parameters are desirable for improving the tandem cell design and improving the quality of the epitaxial layers

Methods

Results

Conclusion