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The statistical photoelectric properties of InGaN/GaN MQWs solar cells under proton irradiation were studied. Three groups of devices were irradiated with 3 MeV proton beams with fluences of 1.0 × 1011 cm−2, 5.0 × 1011 cm−2, and 1.0 × 1012 cm−2. Averaged experiment results showed that the open circuit voltage (VOC) and fill factor (FF) always decreased. In contrast, the short circuit current density (JSC) and photoelectric conversion efficiency (η) increased first and then decreased with the increase of fluence. Firstly, the donor-like defects of InGaN layer in active region played a major role in increasing JSC and η when the fluence was relatively low. Due to the introduction of donor-like defects, extra free electrons were produced, which lead to an increase in the number of effective carriers. With the further increasing of proton fluence, the number of free electrons caused by donor-like defects in the used InGaN material (low indium component) increased slowly due to pinning effect. However, additional point defects (Ga vacancies) increased significantly. Ga vacancies can act as effective non-radiative recombination centers, thereby reducing the number of effective carriers. The combined effect of pinning effect and non-radiative recombination process is responsible for the first increase and subsequent decline of JSC and η.

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A high-efficiency InGaN photo cell irradiated by 532 nm laser (at green wavelength) with AlGaN electron blocking layer (EBL) is proposed based on the blue-green light window effect of seawater. First, the InGaN/GaN multiple quantum wells (MQWs) structured material intercalated with AlGaN EBL was designed and grown for InGaN photo cells. Then, using atomic force microscopy, X-ray diffraction, and photoluminescence measurements, it was found that the insertion of AlGaN EBL can effectively reduce the defect density and improve the steepness of the interface in the active region. Further, based on these material characteristics, the performance of the InGaN photo cells with AlGaN EBL was evaluated in Silvaco software under 532 nm laser irradiation. The results show that the introduction of AlGaN EBL in InGaN photo cell can not only decrease the non-radiative recombination rates, but also reduce the piezoelectric polarization effect, which contribute to the transport of effective photo-generated carriers and eventually improve the conversion efficiency by 13.325% compared to that with conventional structure. These findings provide critical new insights on high-efficiency GaN-based Photo Cell irradiated by 532 nm laser in the application of underwater communications.

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