Self-powered broadband photodetectors exhibit excellent self-powered and wide-band photoresponse from visible to infrared region and attract enormous attention due to their promising applications in imaging, sensing, and optical communication. PbSe colloidal quantum dots (CQDs) and halide perovskites nanocrystals (NCs) are commonly used for photodetectors due to their strong absorption capability, tunable bandgap, and high aspect ratio. However, due to suffering from low charge carrier mobility and high trap density, the performance of individual PbSe CQDs and perovskites-based photodetectors is not satisfactory. Integration of PbSe CQDs with inorganic mixed-halide perovskite nanomaterials can provide an opportunity to overcome these drawbacks. In this work, a hybrid nanocomposite of PbSe CQDs blended with all-inorganic mixed halide perovskite NCs is integrated to fabricate bulk-heterojunction-based high-performance photodetectors. The transportation of photogenerated carriers is enhanced by employing electrons-and holes-extracting layers. As a result, the photoresponsivity of 6.16 A W −1 and a specific detectivity of 5.96 × 10 13 Jones with an ON/OFF current ratio of 10 5 is obtained for bulk-heterojunction photodetector ITO/ZnO/PbSe:CsPbBr 1.5 I 1.5 /P3HT/Au in the self-powered mode. Meanwhile, the device performance of the fabricated photodetector is numerically simulated by using Technology Computer-Aided Design software, and the physical mechanisms for photogenerated carriers' transportation are discussed in detail.

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Heterojunctions based on low dimensional semiconducting materials are one of the most promising alternatives for next-generation optoelectronic devices. By choosing different dopants in high-quality semiconducting nanomaterials, p-n junctions can be realized with tailored energy band alignments. Also, p-n bulkheterojunctions (BHJs) based photodetectors have shown high detectivity because of the suppressed dark current and high photocurrent, which are due to the larger built-in electric potential within the depletion region and can significantly improve the quantum efficiency by reducing the carriers' recombination. In this work, PbSe quantum dots (QDs) blended with ZnO nanocrystals (NCs) were used as the n-type layer, while CsPbBr 3 NCs doped with P3HT were used as the p-type layer; as a result, a p-n BHJ was formed with a strong built-in electric field. Consequently, such a kind of p-n BHJ photodetector ITO/ZnO/PbSe:ZnO/CsPbBr 3 :P3HT/P3HT/Au showed a high ON/OFF current ratio of 10 5 with a photoresponsivity of 1.4 A/W and specific detectivity of 6.59 × 10 14 Jones under 0.1 mW/cm 2 532 nm illumination in self-driven mode. Moreover, the simulation performed by TCAD also agrees well with our experimental results, and the underlying physical mechanism for enhanced performance is discussed in detail for this type of p-n BHJ photodetector.

Solar energy is the most convenient and reliable energy source among all renewable energy resources and an efficient photovoltaic device is required to convert this energy into utilizable energy. Different types of solar cells (SC) are commercially available. However, various parameters need to be optimized to get maximum efficiency from a SC. In this study we have presented a SC model in which dependence of quantum efficiency (QE) on various parameters has been investigated. The mobility of the carriers has been varied with wide range along with the carrier life time (LT). Results show that maximum efficiencies can be achieved up to 11.10% and 10.81% keeping the electron and hole mobility to be 1500 cm 2 V -1 s -1 and 300 cm 2 V -1 s -1 respectively with electron and hole carrier LT to be 3ns and 7ns respectively. The effect of surface recombination velocity (SRV) has also been brought under observation and the maximum efficiency is found to be 13.75% at electron and hole SRV equal to be 10 3 ms -1 . Results shows that the higher photovoltaic efficiencies can be achieved by increasing the mobility and carrier LT while decreasing the surface recombination velocities.

The fabrication of high‐speed electronic and communication devices has rapidly grown the demand for high mobility semiconductors. However, their high cost and complex fabrication process make them less attractive for the consumer market and industrial applications. Indium nitride (InN) can be a potential candidate to fulfill industrial requirements due to simple and low‐cost fabrication process as well as unique electronic properties such as narrow direct bandgap and high electron mobility. In this work, 3 µm thick InN epilayer is grown on (0001) gallium nitride (GaN)/Sapphire template under In‐rich conditions with different In/N flux ratios by molecular beam epitaxy. The sharp InN/GaN interface monolayers with the In‐polar growth are observed, which assure the precise control of the growth parameters. The directly probed electron mobility of 3610 cm2 V‐1 s‐1 is measured with an unintentionally doped electron density of 2.24 × 1017 cm‐3. The screw dislocation and edge dislocation densities are calculated to be 2.56 × 108 and 0.92 × 1010 cm‐2, respectively. The step‐flow growth with the average surface roughness of 0.23 nm for 1 × 1 µm2 is confirmed. The high quality and high mobility InN film make it a potential candidate for high‐speed electronic/optoelectronic devices.

The demand for charge‐coupled device (CCD) imagers has surged exponentially during the last decade owing to their exceptionally high quality and low noise imaging. However, they are still confronting the performance constraints of high operation power, low speed, and limited charge integration. Here, the electric‐dipole gated phototransistor operation without external gate bias is reported by using high‐k HfO2 dielectric material. The electrostatic coupling of photogenerated charges from the Si with the graphene channel through a 10 nm HfO2 layer is demonstrated. The device exhibits remarkable performance in the broadband spectrum (266–1342 nm) at low drain bias voltage. The high values of responsivity, external quantum efficiency, and detectivity of 3.7 × 103 A W−1, 0.72 × 104, and 6.20 × 1013 cmHz½ W−1, respectively, for 800 nm wavelength and 3.3 × 103 A W−1, 1.31 × 104, and 5.61 × 1013 cmHz½ W−1, respectively, for 400 nm wavelength without gate are achieved. This discovery may potentially eliminate the requirement for gate terminals from commercial CCD devices. The power efficient features of this gateless image sensor can be fabricated at the industrial scale for the future machine vision market.

Two-dimensional materials have modernized a broad interest in electronic devices. Along with many advantages, their atomic-level thickness makes them sensitive under high electrical stress. This work proposes a protection design using a Graphene/Silicon (Gr/Si) Schottky diode as the protective device, which helps to improve the endurance for unwanted fluctuations in operating voltage of 2D heterostructure-based devices. In this scheme, the 2D heterostructure was configured parallel with the protective device (Gr/Si diode) for electrical measurements. It was found that Gr/Si diode handles a large portion of initial surge current peaks, which significantly increases the durability and lifetime of 2D material-based heterostructure devices. This scheme potentially bridges mature CMOS technology and novel 2D-based heterostructure applications for robust futuristic devices.

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