Gallium Doping Effects for Improving Switching Performance of p-Type Copper(I) Oxide Thin-Film Transistors

Abstract

Copper(I) oxide (Cu 2 O), which is obtained from copper(II) oxide (CuO) through a reduction process, is a p-type oxide material with a band gap of 2.1−2.4 eV. However, the switching performance of typical Cu 2 O thin-film transistors (TFTs) is poor because the reduction process increases the concentration of oxygen vacancies (V O ), which interfere with the conduction of hole carriers. Ga with high oxygen affinity was doped in Cu 2 O thin films to decrease V O during the reduction process. As a result, the V O concentration of 1.56 at % for Ga-doped Cu 2 O (Ga:Cu 2 O) thin films decreased from 20.2 to 7.5% compared to pristine Cu 2 O thin films. Accordingly, the subthreshold swing or S-factor, on/off-current ratio (I on/off ), saturation mobility (μ sat ), and threshold voltage (V th ) of Ga:Cu 2 O TFTs were improved compared to pristine Cu 2 O TFTs with values of 7.72 from 12.50 V/dec, 1.22 × 10 4 from 2.74 × 10 2 , 0.74 from 0.46 cm 2 /Vs, and −4.56 from −8.06 V, respectively. These results indicate that Ga plays an important role in improving the switching performance of p-type Cu 2 O TFT.

Progressive p-channel vertical transistors fabricated using electrodeposited copper oxide designed with grain boundary tunability

“…18,22,39 In addition, it should be noted that the SS and on/off current ratio are preferably better than those from previously reported planar p-type transistors (Table S1, ESI †) and vertical n-type transistors. 40,41 The channel coating process provides extraordinarily good electrodeposition, and existing methods, such as conventional sputtering and sol-gel processes, cannot produce artificially vertically aligned GBs in the oxide channel layers.…”

Effects of Iodine Doping on Electrical Characteristics of Solution-Processed Copper Oxide Thin-Film Transistors

“…Recent studies have mostly focused on copper oxide (CuO) semiconductors for electronics and energy devices because it offers the advantages of non-toxicity, cost-effectiveness, and abundance. To meet the demand for high-performance p-channel devices, Bae et al enhanced the performance of copper-based TFTs by doping the semiconductor film with gallium atoms to reduce oxygen vacancies, which are known to interfere with the conduction of hole carriers [14]. Moreover, Baig et al demonstrated that the doping of CuO with yttrium atoms could enhance the device performance [15].…”

High Performance of Solution-Processed Amorphous p-Channel Copper-Tin-Sulfur-Gallium Oxide Thin-Film Transistors by UV/O3 Photocuring

“…The surface morphology of Al 2 O 3 with R RMS of 0.18 nm is shown in Figure S3b. Generally, a TFT based on a high- k dielectric material such as Al 2 O 3 as the GI performs well at a lower operating voltage. − Figure c shows the thermogravimetric and differential thermal analysis (TG-DTA) to examine the thermal stability of the CTSGO precursor solution. TG-DTA was performed in a N 2 atmosphere with a heating rate of 10 °C min –1 .…”