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Recently, β-Ga2O3 solar-blind photodetectors (PDs) have been extensively investigated for a wide range of civil and military applications. Among them, the metal-semiconductor-metal (MSM) structure is one of the most popular candidates due to the merits of fabrication simplicity, the need for only one single-dopant active layer, easy integration with readout circuitry, high quantum efficiency, etc. However, there is generally a tradeoff between sensitivity and response speed due to the specific internal gain mechanism. In this work, MSM PDs based on the molecular beam epitaxy-grown β-Ga2O3 film were fabricated, and the metal/semiconductor (M/S) interfacial properties were tailored through the low-energy Ar-plasma pretreatment, resulting in the localized oxygen deficiency and a sharper interface. Accordingly, the PD sensitivity was dramatically improved, and the advantage of internal gain, i.e., high quantum efficiency, was preserved or became even larger. For example, the 60-W pretreated sample exhibited a high responsivity (R) of 8.41 A/W and a large specific detectivity (D*) of 1.24 × 1014 Jones, both increasing by one order of magnitude in comparison with the untreated sample. More interestingly, the response speed was unexpectedly accelerated, which is ascribed to the rapid and direct tunneling of electrons at the M/S interface as well as to the reduction in RC time constant based on the data analysis and the underlying physical principle discussion. The treatment conditions can be further optimized to counterbalance some side effects. These findings reveal an efficient technique for comprehensively improving the performance of β-Ga2O3 solar-blind PDs.Recently, β-Ga2O3 solar-blind photodetectors (PDs) have been extensively investigated for a wide range of civil and military applications. Among them, the metal-semiconductor-metal (MSM) structure is one of the most popular candidates due to the merits of fabrication simplicity, the need for only one single-dopant active layer, easy integration with readout circuitry, high quantum efficiency, etc. However, there is generally a tradeoff between sensitivity and response speed due to the specific internal gain mechanism. In this work, MSM PDs based on the molecular beam epitaxy-grown β-Ga2O3 film were fabricated, and the metal/semiconductor (M/S) interfacial properties were tailored through the low-energy Ar-plasma pretreatment, resulting in the localized oxygen deficiency and a sharper interface. Accordingly, the PD sensitivity was dramatically improved, and the advantage of internal gain, i.e., high quantum efficiency, was preserved or became even larger. For example, the 60-W pretreated sample exhibited a...

Light-induced degradation has been identified to be a critical issue for most silicon-based solar cell technologies. This study presents an observation of an opposite light-induced enhancement (LIE) effect in photovoltaic performance in poly(3,4-ethylthiophene):polystyrenesulfonate/n-Si organic-inorganic hybrid solar cells. The reduced density of interface states under light soaking (LS) is found to be responsible for the LIE of the hybrid solar cells. An increased minor carrier lifetime under LS and a switchable photoluminescence intensity while applying a voltage bias are observed, providing evidence for the underlying physical mechanism.

In this work, a magnesium (Mg) thin film with a low work function is introduced to obtain a downward energy band at the rear surface of a hybrid solar cell to achieve the function of a back surface field (BSF) similar to the conventional n-n+ high-low junction, i.e., favouring the majority carrier transport and suppressing minority carrier recombination. The open circuit voltages (Voc) of the hybrid solar cells with the Mg BSF layer achieve a clear improvement over those containing only the conventional metal electrode (e.g., Ag), resulting in an increase in the power conversion efficiency (PCE) of the hybrid solar cells from 9.2% to 12.3%. The Suns-Voc measurement determined using a Sinton tool gives Voc as a function of light intensity and shows that Voc increases linearly with the light intensity for the solar cell with the Mg BSF but increases first and then stabilises for the cells without the Mg BSF. This result is attributed to a difference in back surface recombination, further confirming the effi...

The use of polystyrenesulfonate (PSS) thin films in a high-quality passivation scheme involving the suppression of minority carrier recombination at the silicon surface is presented. PSS has been used as a dispersant for aqueous poly-3,4-ethylenedioxythiophene. In this work, PSS is coated as a form of thin film on a Si surface. A millisecond level minority carrier lifetime on a high resistivity Si wafer is obtained. The film thickness, oxygen content, and relative humidity are found to be important factors affecting the passivation quality. While applied to low resistivity silicon wafers, which are widely used for photovoltaic cell fabrication, this scheme yields relatively shorter lifetime, for example, 2.40 ms on n-type and 2.05 ms on p-type wafers with a resistivity of 1–5 Ω·cm. However, these lifetimes are still high enough to obtain high implied open circuit voltages (Voc) of 708 mV and 697 mV for n-type and p-type wafers, respectively. The formation of oxides at the PSS/Si interface is suggested to ...