This article demonstrates changes in the structures of poly (3,4-ethylene dioxythiophene): polystyrene sulfonate (PEDOT: PSS) with the addition of organic additives. The mechanisms of PEDOT: PSS are analyzed using X-ray photoelectron spectroscopy (XPS), cross-sectional images obtained from scanning electron microscopy (SEM), and contact angles. In this paper, a bond-breaking reaction and phase separation are successfully found to occur between PEDOT: PSS molecules and the organic additives. Our research also finds that this bond-breaking reaction and phase separation exist in the PEDOT: PSS–sorbitol–maltitol film at the same time. The addition of organic additives will improve the optical properties and the moisture stability of PEDOT: PSS films.

In this study, we have investigated the performance of multilayer films of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) treated with one of the perfluorinated carboxylic acids, named trifluoroacetic acid (TFA). According to the increased density of the PEDOT chain under unit area conditions, the sheet resistance (R_sq) has improved from 300 to 65 Ω/sq through additional processing of PEDOT:PSS from single layer to multilayer. After the further treatment with TFA, however, the R_sq of the multilayer PEDOT:PSS was enhanced to 45 Ω/sq, leading to the decline of film thickness from 400 to 270 nm. Both conductivity and work function based on X-ray photoelectron spectroscopy results have built a breakthrough by double-processing because of the higher density of conductive PEDOT chains and the increase of 0.4 eV alternatives to typical indium tin oxide substrate, respectively. This improvement is contributed to the development of more effective transparent electrodes.

A metal-oxide-semiconductor high-electron-mobility transistor (MOS-HEMT) is proposed based on using a Al₂O₃/ZrO₂ stacked layer on conventional AlGaN/GaN HEMT to suppress the gate leakage current, decrease flicker noise, increase high-frequency performance, improve power performance, and enhance the stability after thermal stress or time stress. The MOS-HEMT has a maximum drain current density of 847 mA/mm and peak transconductance of 181 mS/mm. The corresponding subthreshold swing and on/off ratio are 95 mV/dec and 3.3 × 10⁷. The gate leakage current can be reduced by three orders of magnitude due to the Al₂O₃/ZrO₂ stacked layer, which also contributes to the lower flicker noise. The temperature-dependent degradation of drain current density is 26%, which is smaller than the 47% of reference HEMT. The variation of subthreshold characteristics caused by thermal or time stress is smaller than that of the reference case, showing the proposed Al₂O₃/ZrO₂ stacked gate dielectrics are reliable for device applications.

We demonstrated the performance of an Al₂O₃/SiO₂ stack layer AlGaN/GaN metal–oxide semiconductor (MOS) high-electron-mobility transistor (HEMT) combined with a dual surface treatment that used tetramethylammonium hydroxide (TMAH) and hydrochloric acid (HCl) with post-gate annealing (PGA) modulation at 400 °C for 10 min. A remarkable reduction in the reverse gate leakage current (I_G) up to $1.5\times {10}^{-12}\mathrm{A}/\mathrm{mm}$ (@ V_G = −12 V) was observed in the stack layer MOS-HEMT due to the combined treatment. The performance of the dual surface-treated MOS–HEMT was significantly improved, particularly in terms of hysteresis, gate leakage, and subthreshold characteristics, with optimized gate annealing treatment. In addition, an organized gate leakage conduction mechanism in the AlGaN/GaN MOS–HEMT with the Al₂O₃/SiO₂ stack gate dielectric layer was investigated before and after gate annealing treatment and compared with the conventional Schottky gate. The conduction mechanism in the reverse gate bias was Poole–Frankel emission for the Schottky-gate HEMT and the MOS–HEMT before annealing. The dominant conduction mechanism was ohmic/Poole-Frankel at low/medium forward bias. Meanwhile, gate leakage was governed by the hopping conduction mechanism in the MOS–HEMT without gate annealing modulation at a higher forward bias. After post-gate annealing (PGA) treatment, however, the leakage conduction mechanism was dominated by trap-assisted tunneling at the low to medium forward bias region and by Fowler–Nordheim tunneling at the higher forward bias region. Moreover, a decent product of maximum oscillation frequency and gate length (f_max × L_G) was found to reach 27.16 GHz∙µm for the stack layer MOS–HEMT with PGA modulation. The dual surface-treated Al₂O₃/SiO₂ stack layer MOS–HEMT with PGA modulation exhibited decent performance with an I_DMAX of 720 mA/mm, a peak extrinsic transconductance (G_MMAX) of 120 mS/mm, a threshold voltage (V_TH) of −4.8 V, a higher I_ON/I_OFF ratio of approximately $1.2\times {10}^9$, a subthreshold swing of 82 mV/dec, and a cutoff frequency(f_t)/maximum frequency of (f_max) of 7.5/13.58 GHz.

Porous anodic aluminum oxide (AAO) is deposited on a 5 cm × 5 cm tin‐doped indium oxide (ITO)/glass substrate, and the AAO/ITO/glass structure thus formed is used to reduce the amount of unreacted Al inside the AAO template, thereby reducing the transmittance of the AAO/glass structure. The enhancement of transmittance is achieved by modulating the diameter of the pores and varying the applied bias. The proposed AAO can be used at a high applied bias (up to 120 V) to improve the uniformity of the current density. Following pore‐widening treatment and posttreatment annealing, the morphologies and transmittance of the AAO/ITO/glass structure were also investigated.

Both β‐FeSi₂ and BaSi₂ are silicides and have large absorption coefficients; thus they are very promising Si‐based new materials for solar cell applications. In this paper, the dc I‐V characteristics of n‐Si/i‐βFeSi₂/p‐Si and n‐Si/i‐BaSi₂/p‐Si thin film solar cells are investigated by solving the charge transport equations with optical generations. The diffusion current densities of free electron and hole are calculated first. Then the drift current density in the depletion regions is obtained. The total current density is the sum of diffusion and drift current densities. The conversion efficiencies are obtained from the calculated I‐V curves. The optimum conversion efficiency of n‐Si/i‐βFeSi₂/p‐Si thin film solar cell is 27.8% and that of n‐Si/i‐BaSi₂/p‐Si thin film solar cell is 30.4%, both are larger than that of Si n‐i‐p solar cell (η is 20.6%). These results are consistent with their absorption spectrum. The calculated conversion efficiency of Si n‐i‐p solar cell is consistent with the reported researches. Therefore, these calculation results are valid in this work.