A homojunction-structured amorphous indium gallium zinc oxide (a-IGZO) phototransistor that can detect visible light is reported. The key element of this technology is an absorption layer composed of hydrogen-doped a-IGZO. This absorption layer is fabricated by simple hydrogen plasma doping, and subgap states are induced by increasing the amount of hydrogen impurities. These subgap states, which lead to a higher number of photoexcited carriers and aggravate the instability under negative bias illumination stress, enabled the detection of a wide range of visible light (400-700 nm). The optimal condition of the hydrogen-doped absorption layer (HAL) is fabricated at a hydrogen partial pressure ratio of 2%. As a result, the optimized a-IGZO phototransistor with the HAL exhibits a high photoresponsivity of 1932.6 A/W, a photosensitivity of 3.85 × 10, and a detectivity of 6.93 × 10 Jones under 635 nm light illumination.

This study reports a low‐temperature processable, resistive switching (RS) device based on an inorganic–organic hybrid perovskite, i.e., methylammonium lead iodide (CH3NH3PbI3 or MAPbI3) via a fast deposition–crystallization method, as the multifunctional insulator layer to form metal/insulator/metal structure in which Al and p+‐Si wafer are used as the top and the bottom metal electrodes, respectively. The MAPbI3‐RS device shows acceptable RS characteristics with a switching window of 103 at a low voltage region (≈5 V), a stable endurance during 200 cycles, and a high retention for a prolonged time at 104 s. The operation mechanism of the MAPbI3‐RS device is based on ion (simultaneously vacancy) migration, especially iodine ions, which is analogous to that of oxygen ions in the conventional oxide‐based RS devices, confirmed through X‐ray photoelectron spectroscopy and energy‐dispersive X‐ray spectroscopy measurements. Furthermore, unusual multiresistance states are achieved from the MAPbI3‐RS device under light illumination due to the photosensitivity of MAPbI3.

We investigated the use of high-pressure gases as an activation energy source for amorphous indium-gallium-zinc-oxide (a-IGZO) thin film transistors (TFTs). High-pressure annealing (HPA) in nitrogen (N2) and oxygen (O2) gases was applied to activate a-IGZO TFTs at 100 °C at pressures in the range from 0.5 to 4 MPa. Activation of the a-IGZO TFTs during HPA is attributed to the effect of the high-pressure environment, so that the activation energy is supplied from the kinetic energy of the gas molecules. We reduced the activation temperature from 300 °C to 100 °C via the use of HPA. The electrical characteristics of a-IGZO TFTs annealed in O2 at 2 MPa were superior to those annealed in N2 at 4 MPa, despite the lower pressure. For O2 HPA under 2 MPa at 100 °C, the field effect mobility and the threshold voltage shift under positive bias stress were improved by 9.00 to 10.58 cm2/V.s and 3.89 to 2.64 V, respectively. This is attributed to not only the effects of the pressurizing effect but also the metal-oxide construction effect which assists to facilitate the formation of channel layer and reduces oxygen vacancies, served as electron trap sites.

We present a solution-processed oxide absorption layer (SAL) for detecting visible light of long wavelengths (635 and 532 nm) for indium–gallium–zinc oxide (IGZO) phototransistors. The SALs were deposited onto sputtered IGZO using precursor solutions composed of IGZO, which have the same atomic configuration as that of the channel layer, resulting in superior interface characteristics. We artificially generated subgap states in the SAL using a low annealing temperature (200 °C), minimizing the degradation of the electrical characteristics of thin-film transistor. These subgap states improved the photoelectron generation in SALs under visible light of long wavelength despite the wide band gap of IGZO (∼3.7 eV). As a result, IGZO phototransistors with SALs have both high optical transparency and superior optoelectronic characteristics such as a high photoresponsivity of 206 A/W and photosensitivity of ∼106 under the influence of a green (532 nm) laser. Furthermore, endurance tests proved that the IGZO phototransistor with SALs can operate stably under red laser illumination switched on and off at 0.05 Hz for 7200 s.

To broaden the availability and application of metal-oxide (M-O)-based optoelectronic devices, we suggest heterogeneous phototransistors composed of In-Ga-Zn-O (IGZO) and methylammonium lead iodide (CHNHPbI) layers, which act as the amplifier layer (channel layer) and absorption layer, respectively. These heterogeneous phototransistors showed low persistence photocurrent compared with IGZO-only phototransistors and exhibited high photoresponsivity of 61 A/W, photosensitivity of 3.48 × 10, detectivity of 9.42 × 10 Jones, external quantum efficiency of 154% in an optimized structure, and high photoresponsivity under water exposure via the deposition of silicon dioxide as a passivation layer. On the basis of these electrical results and various analyses, we determined that CHNHPbI could be activated as a light absorption layer, current barrier, and plasma damage blocking layer, which would serve to widen the range of applications of M-O-based optoelectronic devices with high photoresponsivity and reliability under visible light illumination.