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At present, the application of ZnSnN2 as an active layer in optoelectronic devices is dramatically limited due to its high carrier concentration. It is suggested that off-stoichiometry of cations might be a promising cure. In this work, Zn-Sn-N films with 0.60, 0.67, and 0.85 Zn/(Zn + Sn) ratios were, respectively, fabricated by DC magnetron sputtering. In spite of off-stoichiometry, the films all exhibited a cation-disordered wurtzitelike ZnSnN2 dominated phase except that the crystallinity was decreased with an increasing Zn/(Zn + Sn) ratio. In agreement with the cation-disordered structure, all the Zn-Sn-N films illustrated Raman spectra of a phonon-glasslike characteristic. The refractive index of the films was increased with the Zn/(Zn + Sn) ratio over a wide wavelength range, for example, from 1.990 to 2.459 at the wavelength of 500 nm. The direct optical bandgap of the films varied from 1.36 to 1.68 eV. Most strikingly, an electron concentration of magnitude down to 1016 cm−3 and a very low resistivity down to 10−2 Ω cm were reached for 0.67 and 0.85 Zn/(Zn + Sn) films, respectively. It is highly desirable that both semiconducting and conducting characteristics can be achieved in the Zn-Sn-N material system, which is highly beneficial to its applications in various optoelectronic devices. [ABSTRACT FROM AUTHOR]

High-field-effect-mobility InSnZnO thin-film transistors (TFTs) are prepared through Al-induced microstructure regularization (AIMR) at an annealing temperature lower to 400 °C. Spherical crystalline particles are distributed throughout the back channel near the Al layer, while an amorphous phase still represents the front channel but with enhanced microstructure ordering. Especially, the packing density is distinctly increased, and oxygen vacancies are largely reduced. The optimized TFT exhibits excellent performance with a steep sub-threshold swing of 0.18 V/dec, a high on/off current ratio of 2.5 × 108, a threshold voltage of −0.21 V, and a small threshold voltage shift of −0.24 V under negative bias stress (−20 V, 3600 s), especially a remarkable field-effect mobility boosted to 53.2 cm2/V s compared to 19.1 cm2/V s for the TFT without the Al layer. After Al removal, the TFT performance shows no obvious degradation, implying good compatibility of the AIMR technique to the current device process. [ABSTRACT FROM AUTHOR]

P-type Cu-Sn-I thin films with different Sn contents (CSn) were fabricated in air via a simple and low-cost spin-coating method. Sn additive facilitates the amorphization of CuI, and a complete amorphous phase of Cu-Sn-I film is achieved at CSn =15%. With increasing CSn, the optical bandgap increases and refractive index decreases, probably due to the influence of Sn-additive on both the electronic structure and phase state of the films. The air-processed Sn-free CuI films show p-type conduction with hole mobility and a concentration of 17.3 cm2/V−1 s−1 and 1.1 × 1019 cm−3, and an increasing trend of resistivity is observed along with a large drop in hole concentration during the Sn-inspired amorphization process. Moreover, transparent Cu-Sn-I/IGZO p–n junctions were constructed, exhibiting the optimum rectifying characteristic at CSn = 15% with a forward-to-reverse ratio of 6.2 × 103. [ABSTRACT FROM AUTHOR]

Amorphous Ga2O3:CdO thin films and their thin-film transistor (TFT) photodetectors were fabricated via a simple and low-cost spin-coating method. The film optical bandgap and TFT electrical parameters can be effectively regulated via changing the Cd content. The optimized Ga2O3:CdO TFT photodetector exhibited a responsivity of 2.17 A/W and a high UV/vis. rejection of 1.88 × 104 under 260 nm at small working biases, which are comparable or even superior to the recently reported results. Systematic comparison between metal-semiconductor-metal- and TFT-type photodetectors further confirmed that our TFT photodetectors had superior detective performance and lower electrical power consumption. [ABSTRACT FROM AUTHOR]

Separative extended-gate AlGaAs/GaAs high electron mobility transistor (HEMT) biosensors based on the capacitance change strategy are proposed and fabricated. The working mechanism underlying this strategy is clearly clarified via examining the capacitance evolution on biorecognition and the capacitance matching issue between the HEMT and the sensing pad. The fabricated biosensors demonstrate a good linear current/voltage response to a label-free prostate-specific antigen (PSA) target over a broad concentration range of 100 fg/ml to 10 ng/ml in both 0.1× and 1× phosphate buffered saline solutions. Specifically, the sensitivity variation approaches 8.7% dec−1 at the critical concentration level of 2–8 ng/ml that enters the normal PSA region in the human body. The advantages of high sensitivity, low-cost, and convenience of usage make the proposed HEMT biosensors potential candidates for prostate cancer diagnosis. [ABSTRACT FROM AUTHOR]