In the last issue, we introduced cadmium telluride (CdTe) thin film solar cells and copper indium gallium selenide (CIGS) thin film solar cells, but there are many types of thin film solar cells that can be used. In this issue, Millennial Solar will introduce amorphous silicon (a-Si). Thin film solar cells and gallium arsenide (GaAs) thin film solar cells.

Amorphous silicon (a-Si) thin film solar cells

In 1975, Spear and Lecombe first observed doping in amorphous silicon (a-Si), and a year later, in 1976, demonstrated that amorphous silicon (a-Si) thin-film solar cells could be produced. There were great expectations for this technology, but the material encountered several problems, such as relatively poor efficiency.

Unlike other thin-film solar panels, amorphous silicon (a-Si) cells do not include an n-p heterojunction, but rather a p-i-n or n-i-p configuration, which differs from n-p heterojunctions by the addition of i-type or intrinsic semiconductors. There are two approaches to manufacturing amorphous silicon (a-Si) thin film solar panels by processing glass sheets or flexible substrates. The efficiency of a-Si solar cells is currently set at 14.0%. Regardless of the route to manufacturing amorphous silicon (a-Si) thin film solar panels, the following steps are part of the process: First, the substrate is conditioned, the TCO and back reflector are placed under the deposition process, and then the thin A base layer of hydrogenated amorphous silicon (a-Si:H) is placed over the electrodes, and the cells are connected into a series of monoliths via laser scribing and silicon layers. The cell is finally assembled and packaged, with the frame and electrical connections applied. While small amounts of cheap materials are required to make amorphous silicon (a-Si), it is relatively expensive because the conductive glass for these panels is expensive and the process is slow, setting the total cost of the panels at $0.69/W. The technology currently accounts for 2.0% of the photovoltaic module retail market.

Current Continuity Testing System

Current Continuity Testing System is specially designed for the 10.11 high and low temperature cycle test clauses and 10.12 humidity and freezing test clauses in the IEC61215 standard. It mainly includes providing stable DC power, current recording, temperature recording and temperature control functions. Through temperature control of the DC power supply, it can monitor multiple currents and temperatures in real time for a long time. Used in conjunction with a high and low temperature cycle box, it can monitor the internal circuit continuity of multiple components. Determine the fatigue resistance of the material, the rationality of the lamination process, and the stability of the welding quality of the solar cell module in high and low temperature alternating environments.

E-mail: market@millennialsolar.cn

Gallium Arsenide (GaAs) Thin Film Solar Cells

Gallium arsenide (GaAs) thin-film solar panels were a breakthrough made by Zores Alferov and his students in 1967, and the first gallium arsenide (GaAs) thin-film solar cell was manufactured in 1970. The team persisted in making gallium arsenide semiconductors, and about 10 years later, in 1980, the technology was being investigated for specific applications such as spacecraft and satellites.

The manufacturing process of GaAs thin film solar cells is more complex than that of conventional thin film solar cells.

The first step is to grow the material. In this step, the GaAs buffer grows on the Si substrate by undergoing several temperature changes and different chemical processes, ultimately creating a layer for the cells.

After growth in GaAs buffer, the substrate is processed to create cells. The first step is to deposit a platinum (Pt)/gold (Au) layer (10/50 nm) that will serve as the bonding material and electrode for the GaAs solar cell, followed by the bonding process on the substrate.

After the bonding process is completed, the GaAs epitaxial layer grown on the Si substrate is placed on the new substrate. To complete the assembly process, a 20/30/20/200 nm Pt/Titanium (Ti)/Pt/Au layer is deposited on the top contact layer via electron beam evaporation.

Because GaAs PV cells are multi-junction III-V solar cells composed of graded buffers, they can achieve high efficiencies of up to 39.2%, but the cost of fabrication time, materials and high-growth materials make them less suitable for terrestrial applications. Viable options. The rated efficiency of gallium arsenide thin film solar cells is recorded at 29.1%.

The cost of these III-V thin-film solar cells has increased from $70/watt to $170/watt, but NREL says prices can drop to $0.50/watt in the future. Because this is such an expensive experimental technology, it is not mass-produced and is used primarily for space applications, with minimal market share.

This ends the sharing of thin film cell materials. Photovoltaics have a variety of products and technologies. Millennial Solar will continue to share information on the photovoltaic industry in the next issue.