Transport mechanisms in hyperdoped silicon solar cells

Abstract

According to intermediate band (IB) theory, it is possible to increase the efficiency of a solar cell by boosting its ability to absorb low-energy photons. In this study, we used a hyperdoped semiconductor approach for this theory to create a proof of concept of different silicon-based intermediate band solar cells. Preliminary results show an increase in the external quantum efficiency (EQE) in the silicon sub-bandgap region. This result points to sub-bandgap absorption in silicon having not only a direct application in solar cells but also in other areas such as infrared photodetectors. To establish the transport mechanisms in the hyperdoped semiconductors within a solar cell, we measured the J-V characteristic at different temperatures. We carried out the measurements in both dark and illuminated conditions. To explain the behavior of the measurements, we proposed a new model with three elements for the IB solar cell. This model is similar to the classic two-diodes solar cell model but it is necessary to include a new limiting current element in series with one of the diodes. The proposed model is also compatible with an impurity band formation within silicon bandgap. At high temperatures, the distance between the intermediate band and the n-type amorphous silicon conduction band is close enough and both bands are contacted. As the temperature decreases, the distance between the bands increases and therefore this process becomes more limiting.

Development of Hetero-Junction Silicon Solar Cells with Intrinsic Thin Layer: A Review

“…In this work [64], the authors failed to increase the efficiency of the HIT solar cell. However, at the same time, we believe that this direction-the direction of engineering and the study of the properties of heterojunctions-is worth moving towards.…”

“…As an example of the successful application of such an approach, I would like to describe the work of scientists from Spain [64]. The authors made a HIT solar cell: in its design, a hyperdoped layer was applied to the surface of crystalline silicon-photovoltaic cell based on intermediate band (IB) semiconductors (IB solar cell, or IBSC) (Figure 4).…”

“…As an example of the successful application of such an approach, I would like scribe the work of scientists from Spain [64]. The authors made a HIT solar cel design, a hyperdoped layer was applied to the surface of crystalline silicon-photo cell based on intermediate band (IB) semiconductors (IB solar cell, or IBSC) (Figur In this study, the researchers created various IBSCs based on a hyperdoped silicon semiconductor with Ti and V. These cells have an efficiency of 2.6% and 1.9%, respectively, and exhibit a silicon subbandgap EQE.…”