Plasma-Deposited Multilayer GaP/Si p-i-n Structure for Tandem Silicon-Based Solar Cells

Abstract

The possibility of creating an upper junction of multijunction III–V/Si solar cells based on GaP/Si superlattices (SL), grown using a combination of plasma-enhanced atomic-layer deposition (PEALD) and plasma-enhanced chemical vapor deposition (PECVD) technologies at a temperature not exceeding 400 °C, is shown. Structural and electrophysical studies of GaP/Si SL were performed and the photovoltaic properties of solar cells based on them were explored. The obtained GaP/Si SL epitaxially grown on the silicon substrate has a crystalline structure. According to the electrochemical capacitance–voltage (ECV) measurements, oscillations on the electron concentration profile were observed with a period corresponding to the thickness of the layers. The spectral dependence of the external quantum efficiency (EQE) shows the broadening of the sensitivity to the long-wavelength region for solar cells based on GaP/Si SL in comparison with p-i-n structures based on GaP. The obtained results open up the possibility of using GaP/Si SL to increase the spectral sensitivity of the upper junction in double-junction III–V/Si systems.

Recent Advances in the Plasma-Assisted Synthesis of Silicon-Based Thin Films and Nanostructures

“…Recently, Baranov and coworkers studied the growth of GaP/Si superlattices for photovoltaic applications, with GaP layers with a thickness of 3 nm and Si layers with a thickness of 0.5 nm [44] or 1.5 nm [45]. The authors used a hybrid deposition process that employed a standard RF-PECVD in continuous mode for the deposition of the microcrystalline silicon (mc-Si) layers and a PEALD using trimethylgallium (TMG) and phosphine (PH 3 ) for growing the crystalline gallium phosphide (GaP) layers.…”