Transparent P-type Semiconductor Research Articles

Altering the physical properties of NiO thin films grown through the ultrasonic spray pyrolysis method by incorporating impurity lead dopants

The technology of p-type transparent semiconductors is utilized in various fields, and enhancing their performance holds industrial significance. Thus, improving the versatility and efficiency of the p-type transparent conducting oxides (TCO) has become critical for the semiconductor industries and technologies. To be used as hole carrier layes in optoelectronic devices, this study aimed to modify the physical features of nickel oxide (NiO) through a doping approach which may broaden and strengthen the usage of NiO. A cost-effective ultrasonic pyrolysis spray technique was employed for pure and lead (Pb) doped nickel oxide thin film production. The influence of the lead concentration on optical, structural, and morphological traits of the NiO nanostructures was examined via various analyses, including energy-dispersive X-ray spectroscopy (EDAX), scanning electron microscopy (SEM), Photoluminescence, UV–visible spectroscopy, X-Ray Diffraction, and Raman spectroscopy, were utilized to investigate the optical and structural characteristics of these films. In correlation, the X-Ray Diffraction results indicated that the Pb doping induced strain and altered lattice parameters of the grown nanostructures while the cubic phase of NiO maintained. The crystallite size of NiO samples ranged from 31.49 nm to 18.75 nm based on Pb doping concentration which was notably influenced by species and doping content. The UV–vis measurements demonstrated that optical parameters, such as optical band gap, were sensitive to Pb doping ratios. The Raman spectrum analysis confirmed the successful incorporation of Pb ions into NiO. Additionally, the intensity of the PL spectra decreased with increasing Pb content, offering potential applications as window layers in solar cells, smart windows, and other optoelectronic devices.

Semitransparent organic photovoltaics enabled by transparent p-type inorganic semiconductor and near-infrared acceptor

Semitransparent organic photovoltaics (STOPVs) have gained wide attention owing to their promising applications in building-integrated photovoltaics, agrivoltaics, and floating photovoltaics. Organic semiconductors with high charge carrier mobility usually have planar and conjugated structures, thereby showing strong absorption in visible region. In this work, a new concept of incorporating transparent inorganic semiconductors is proposed for high-performance STOPVs. Copper(I) thiocyanate (CuSCN) is a visible-transparent inorganic semiconductor with an ionization potential of 5.45 eV and high hole mobility. The transparency of CuSCN benefits high average visible transmittance (AVT) of STOPVs. The energy levels of CuSCN as donor match those of near-infrared small molecule acceptor BTP-eC9, and the formed heterojunction exhibits an ability of exciton dissociation. High mobility of CuSCN contributes to a more favorable charge transport channel and suppresses charge recombination. The control STOPVs based on PM6/BTP-eC9 exhibit an AVT of 19.0% with a power conversion efficiency (PCE) of 12.7%. Partial replacement of PM6 with CuSCN leads to a 63% increase in transmittance, resulting in a higher AVT of 30.9% and a comparable PCE of 10.8%.

Optoelectronic properties of BiCuOSe p-type oxychalcogenides

BiCuOSe systems are proposed as candidates to develop transparent p-type semiconductors in the visible region. This work reports the characterization results obtained for the BiCuOSe powders, synthesized by the solid-state reaction (SSR) method through mechanical milling, and nanostructured thin films deposited from the same processed powders using the pulsed laser deposition (PLD) technique. Structural characterization through X-ray diffraction (XRD) showed that the material presents a tetragonal structure with an average crystallite size of 21 nm and a preferential orientation in the (1 0 2) plane. The morphological and particle size evolution of BiCuOSe powders is presented as a function of the milling time. Transmission and scanning electron microscopies confirmed the spherical geometry of the particles in the powders and nanosheets like structure for the films. Particle sizes were also estimated, ranging from 10 to 100 nm for powders and 60 to 70 nm for films. The bandgap values, EG, for BiCuOSe powders were estimated from diffuse reflectance spectra using the Kubelka–Munk method, yielding values close to 0.7 eV. For thin films, EG values were estimated using the Tauc method, obtaining values in the range of 0.8–3.5 eV, depending on the annealing treatment. Additionally, electrical properties were measured in all deposited thin films, confirming the p-type conductivity, a minimal resistivity of 0.0735 Ω cm, hole mobility on the order of 88 cm2/Vs, and carrier concentration of 9.7 × 1018 cm−3.

Fabrication of transparent p-CuI/n-ZnO heterojunction with excellent ideality factor

Copper iodide (CuI) is an intrinsically transparent p-type semiconductor with a wide band gap of about 3.1 eV. In this work, Cu3N films were prepared as precursors through high-power impulse magnetron sputtering and then were solid-phase iodinated at room temperature for the preparation of transparent CuI films. Subsequently, transparent p-CuI/n-ZnO heterojunctions were fabricated wherein ZnO layers were deposited by radio frequency magnetron sputtering. After the properties are optimized by annealing, the heterojunctions exhibit significant rectification characteristics. The influence of annealing temperature on the electrical properties of the heterojunctions have been investigated. The optimal ideality factor of about 1.22 can be obtained with a rectification ratio of 1.05 × 105 after the heterojunctions annealing at 100 °C. This value is superior to most of the results reported in the literature. Meanwhile, the light-to-dark current ratio and the transmittance in the visible region of the heterojunction have also been studied. The light-to-dark current ratio is significant at 6.42 × 106. The average transmittance of the heterojunctions is 72.7%. These findings demonstrate the potential applications of CuI for optoelectronic devices and the promising prospects of p-CuI/n-ZnO heterojunction-based photodetectors and other optoelectronic devices.

Insights into the electronic structure of tin(ii) pyrochlore oxides with 5s2 lone pair states as transparent p-type oxide semiconductors

P-type oxide semiconductor is crucial for advanced electronics. This work reveals the development of tin(ii) pyrochlore oxides as transparent p-type oxide semiconductor through synergistic valence band modulation and crystal structural design.

Mild oxygen plasma-treated nickel oxides for performance enhancement of hybrid perovskite light-emitting diodes

Nickel oxide (NiOx), a representative transparent p-type semiconductor, has been a promising candidate for hole transport layer (HTL) in perovskite-based photovoltaic and light-emitting diode (LED) devices due to its high chemical stability and high transparency. However, the interface between the NiOx and perovskite emission layers shows a relatively large electrical barrier for the holes to be transported, which degrades the interfacial electrical properties. To overcome these problems, we suggest a mild oxygen plasma treatment on the NiOx surface to introduce Ni vacancies while retaining its advantages. By controllably forming the Ni vacancies, the hole concentrations could be controlled, which modulated the valence band edge level. This increases the work function of NiOx from 4.979 to 5.364 eV, which facilitates the hole transport at the interface between NiOx HTL and the perovskite emission layer. Ultimately, the overall process leads to improved electroluminescence intensity, reduced driving voltage reduction, and low charge trap density at the interface between the NiOx HTL and the perovskite emission layers. These eventually improved the external quantum efficiency of the perovskite light-emitting diodes.

Effect of grain boundary scattering on carrier mobility and thermoelectric properties of tellurium incorporated copper iodide thin films

Copper iodide (CuI) is a promising p-type transparent semiconductor with many potential applications in range of fields such as transistors, optoelectronics, solar cells, thermal sensors, and energy harvesting. We report compositional, structural, optical, electrical, and thermoelectric properties of optically transparent tellurium (Te) incorporated CuI films, (CuI)1-xTex where x=0–0.09, prepared by ion beam sputtering. The films are composed of γ-CuI with the presence of elemental tellurium clusters in films prepared with high Te concentration sputtering targets. The carrier mobility decreased from 6.9 ± 0.9 cm2V-1s-1 to 0.7 ± 0.1 cm2V-1s-1, and the electrical conductivity from 84.22 ± 8.45 Scm-1 to 3.97 ± 0.40 Scm-1 for the CuI and (CuI)0.91Te0.09 films, respectively, attributed to a transition from polar optical phonon to grain boundary scattering. The change in the mobility-limiting scattering mechanism decreased the power factor from 454 ± 57 μWm-1K-2 for the CuI film to 34 ± 4 μWm-1K-2 for the (CuI)0.91Te0.09 film. Our study shows that modulating the scattering mechanism in transparent thermoelectric materials is a powerful method to tune their thermoelectric properties.

1.37×102 S·cm-1 p-type conductivity LaCuOS films with a very wide optical transparency window of 400-6000 nm

The absence of highly conductive p-type transparent semiconductors has blocked the development of transparent p-n junction devices and electronics, and it is a well-known challenge to achieve highly conductive p-type transparent materials. In this paper, we report the achievement of large area p-type LaCuOS single phase semiconducting and conducting thin films with record high conductivity of 136.7 S·cm-1 and very good optical transparency of 80% at 600 nm and 40% at 5000nm. The optical gap is about 3.15 eV. The LaCuOS film can be semiconductor or conductor by controlling sulphuration. The optical transparency window of 400-6000 nm is amazingly wide, covering wavelengths from visible to middle infrared lights, indicating its potential applications in visible and infrared semiconductor devices and electronics. The Fermi level is very close to the valance band upper edge, suggesting that this material can be an excellent candidate of high work function transparent electrodes for photovoltaic and optoelectronic devices.

High-performance p-channel CuIBr thin-film transistor synthesized from solution in the atmosphere

The p-type transparent semiconductor CuI has a high potential to be used in thin film transistors (TFTs) due to high hole mobility and solution processability. However, the lower copper vacancy formation energy and the subsequent high hole concentration in CuI lead to a low on/off current ratio (ION/IOFF) for CuI TFT devices. The density functional theory results suggest that the copper vacancy formation energy increases with the CuBr content in the Br-doped CuI film, resulting in lower hole concentration. Alloying CuI with CuBr is proposed to reduce the hole concentration in the CuIBr alloy. The CuIBr TFTs with Br content ranging from 0% to 10% were fabricated using the solution method. It is found that the hole mobility decreases from 8 to 1 cm2 V−1 s−1, while the ION/IOFF ratio increases from 102 to 104 with the increasing Br content. The CuIBr TFT with 7.5% Br content exhibits a high hole mobility larger than 5 cm2 V−1 s−1 and high ION/IOFF ratio of 104, which paves the way for inorganic-based CMOS circuits on flexible and transparent substrates.

(LaCrO3) m /SrCrO3 superlattices as transparent p-type semiconductors with finite magnetization.

The electronic and magnetic properties of (LaCrO3) m /SrCrO3 superlattices are investigated using first principles calculations. We show that the magnetic moments in the two CrO2 layers sandwiching the SrO layer compensate each other for even m but give rise to a finite magnetization for odd m, which is explained by charge ordering with Cr3+ and Cr4+ ions arranged in a checkerboard pattern. The Cr4+ ions induce in-gap hole states at the interface, implying that the transparent superlattices are p-type semiconductors. The availability of transparent p-type semiconductors with finite magnetization enables the fabrication of transparent magnetic diodes and transistors, for example, with a multitude of potential technological applications.

The origin of the P-type conductivity for Cu and Ag-doped NiO: Density functional theory study

NiO, as a promising transparent p-type semiconductor, was intensively studied in experiment. Due to the difference of fabrication methods and defects concentration, it is difficult to make meaningful comparisons. In this work, the performance for Cu and Ag-doped NiO is fully evaluated by using the density functional theory method. Electronic structures show Cu and Ag substituting Ni (labeled as Cu Ni and Ag Ni ) are deep acceptors, and the ionization energy ε(0/-) for Cu Ni and Ag Ni are much higher than 0.20 eV. Our studies show the p-type conductivity for Cu and Ag-doped NiO mainly stems from the coexistent Ni vacancies (labeled V Ni ). The ionization energy ε(0/-) for Cu Ni (Ag Ni ) plus V Ni are 0.086 (0.012) eV. Under O-rich condition, the compounds M 2 O 2 and M 2 O (M = Cu and Ag) are promising dopants sources. We expect this work could promote the fundamental understanding of the p-type conductivity for nonstoichiometric NiO as well as the Cu and Ag-doped NiO. The data that supports the findings of this study are available from the corresponding author upon reasonable request.

Transparency and p-Type Conductivity of BeSe Doped with Group VA Atoms: A Hybrid Functional Study

Utilizing a hybrid functional method, the transparency and p-type conductivity of BeSe are investigated. Our studies confirm that N- and P-substituted Se (labeled as NSe and PSe) are promising p-type defects due to their smaller ionization energy. BeN2 and BeP2 are efficient dopant sources for their moderate formation energy. Based on the thermodynamic equilibrium fabrication method together with the rapidly quenching scheme, we find the hole density, induced by NSe (PSe) defects, can reach 4.44 × 1018 (3.83 × 1016) cm–3. A high density of holes, smaller hole effective mass (along the Γ-X and W-X directions, the hole effective masses are 0.466 and 0.759m0 (m0 is the electron’s static mass)), wide band gap, and weak plasmonic effect show that BeSe with NSe defects is an excellent transparent p-type semiconductor. These findings provide significant insight to explore a transparent p-type semiconductor.

(Digital Presentation) Multimodal Encapsulation of p-SnOx to Engineer the Carrier Density for Thin Film Transistor Applications

It has been challenging to synthesize p-type SnOx (1≤x<2) and engineer the electrical properties such as carrier density and mobility due to the narrow processing window and the localized oxygen 2p orbitals near the valence band.We recently reported on the processing of p-type SnOx and an oxide-based p-n heterostructures, demonstrating high on/off rectification ratio (>103), small turn-on voltage (<0.5 V), and low saturation current (~1×10-10 A)1. In order to further understand the p-type oxide and engineer the properties for various electronic device applications, it is important to identify (or establish) the dominating doping and transport mechanisms. The low dopability in p-type SnOx, of which the causation is also closely related to the narrow processing window, needs to be mitigated so that the electrical properties of the material are to be adequately engineered 2, 3.Herein, we report on the multifunctional encapsulation of p-SnOx to limit the surface adsorption of oxygen and selectively permeate hydrogen into the p-SnOx channel for thin film transistor (TFT) applications. Time-of-flight secondary ion mass spectrometry measurements identified that ultra-thin SiO2 as a multifunctional encapsulation layer effectively suppressed the oxygen adsorption on the back channel surface of p-SnOx and augmented hydrogen density across the entire thickness of the channel. Encapsulated p-SnOx-based TFTs demonstrated much-enhanced channel conductance modulation in response to the gate bias applied, featuring higher on-state current and lower off-state current. The relevance between the TFT performance and the effects of oxygen suppression and hydrogen permeation is discussed in regard to the intrinsic and extrinsic doping mechanisms. These results are supported by density-functional-theory calculations. Acknowledgement This work was supported by the U.S. National Science Foundation (NSF) Award No. ECCS-1931088. S.L. and H.W.S. acknowledge the support from the Improvement of Measurement Standards and Technology for Mechanical Metrology (Grant No. 20011028) by KRISS. K.N. was supported by Basic Science Research Program (NRF-2021R11A1A01051246) through the NRF Korea funded by the Ministry of Education. References Lee, D. H.; Park, H.; Clevenger, M.; Kim, H.; Kim, C. S.; Liu, M.; Kim, G.; Song, H. W.; No, K.; Kim, S. Y.; Ko, D.-K.; Lucietto, A.; Park, H.; Lee, S., High-Performance Oxide-Based p–n Heterojunctions Integrating p-SnOx and n-InGaZnO. ACS Applied Materials & Interfaces 2021, 13 (46), 55676-55686.Hautier, G.; Miglio, A.; Ceder, G.; Rignanese, G.-M.; Gonze, X., Identification and design principles of low hole effective mass p-type transparent conducting oxides. Nat Commun 2013, 4.Yim, K.; Youn, Y.; Lee, M.; Yoo, D.; Lee, J.; Cho, S. H.; Han, S., Computational discovery of p-type transparent oxide semiconductors using hydrogen descriptor. npj Computational Materials 2018, 4 (1), 17. Figure 1

Hole Concentration Reduction in CuI by Zn Substitution and its Mechanism: Toward Device Applications.

Copper iodide (CuI) is a promising p-type transparent semiconductor with excellent carrier mobility. However, the high hole concentration in conventionally fabricated CuI including the single crystal hinders its applicability to the channel layer of thin-film transistors. We found that Zn substitution into Cu+ sites can effectively reduce the hole concentration. Experimental and computational examinations showed that the dominant mechanism involved the formation of a defect pair, the Zn-substituted Cu site (ZnCu) and Cu vacancy (VCu), and the simultaneous suppression of VCu arising from the stabilization of Cu+ in the Zn-substituted CuI lattice, rather than hole compensation by the electrons generated from Zn2+ substitution into Cu+ sites. Our results show that the hole concentration of Zn-substituted CuI is tunable in the range of 1014-1018 cm-3, making it suitable for thin-film transistors and hole transport layers in OLEDs.

Chemical Vapor Deposition of Wide-Bandgap p-Type Semiconductor Cuprous Iodide for Optoelectronic Device Applications

Continuous, pinhole-free thin films of transparent conductive materials (TCMs) with p- and n-type conductivity are critical components of optoelectronic devices including photovoltaics (PV), transparent electronics, and LEDs [1]. TCMs with n-type conductivity are widely available in the form of semiconducting oxides [2]; however, p-type TCMs (hole transport materials, HTMs) with suitable conductivity are comparatively rare [1]. Particularly in the rapidly growing field of thin film perovskite PV, device-quality thin films of HTMs with high stability and conductivity are urgently needed to replace the organic HTMs typically employed in perovskite PV research [3]. As such, techniques to deposit inorganic HTM thin films are desired.With a focus on applying HTMs in optoelectronic devices at the commercial scale, these materials must be deposited by a scalable technique yielding thin, continuous, pinhole-free films. Chemical vapor deposition (CVD) is a highly scalable thin film deposition technique widely used in industry, with a proven ability to yield high-quality thin films on large-area substrates [4]. A variety of n-type TCMs are accessible by CVD techniques, but few CVD methods exist for p-type TCMs; examples include atomic layer deposition of NiOx and VOx [5].The cuprous halides (CuX, X = Cl, Br, I), which are optically transparent p-type semiconductors with bandgaps ~3 eV, are promising inorganic HTM candidates. Cuprous iodide is of particular interest due to its low resistivity (~10-2 Ohm·cm), high hole concentration and mobility (~1019 cm-3 and ~1-10 cm2V-1s-1, respectively), and its valence band maximum position (ionization potential: 5.0-5.4 eV), which is well-aligned with common perovskite absorber materials [6]. While CuI crystallite arrays have been obtained by metal-organic CVD [7], CVD of continuous CuI thin films has only been achieved by a two-step vapor conversion process, requiring initial deposition of a copper chalcogen followed by vapor-phase conversion to the halide [6].Our group has recently published a CVD technique enabling direct deposition of continuous CuBr thin films via CVD reaction between hydrogen bromide and vinyltrimethylsilane(hexafluoroacetylacetonato)copper(I) [Cu(hfac)(vtms)] [8], and this technique has been extended to deposition of CuI. X-ray photoelectron spectroscopy indicates pure CuI films with an atomic ratio of approximately 1:1 Cu:I, and x-ray diffraction confirms deposition of γ-CuI. Similar to our observations for CuBr films, substrate identity has significant effects on CuI film continuity. Progress towards CVD of continuous CuI films on substrates of interest for practical application in optoelectronic devices will be discussed, with a particular focus on perovskite PV.[1] A. N. Fioretti and M. Morales-Masis, "Bridging the p-type transparent conductive materials gap: synthesis approaches for disperse valence band materials," J. Photon. Energy, 10, 042002 (2020).[2] M. Morales-Masis, S. De Wolf, R. Woods-Robinson, J. W. Ager, and C. Ballif, "Transparent Electrodes for Efficient Optoelectronics," Adv. Electron. Mater., 3, 1600529 (2017).[3] B. Gil, A. J. Yun, Y. Lee, J. Kim, B. Lee, and B. Park, "Recent Progress in Inorganic Hole Transport Materials for Efficient and Stable Perovskite Solar Cells," Electron. Mater. Lett., 15, 505 (2019).[4] R. Gordon, "Chemical Vapor Deposition of Coatings on Glass," J. Non-Cryst. Solids, 218, 81 (1997).[5] J. A. Raiford, S. T. Oyakhire, and S. F. Bent, "Applications of atomic layer deposition and chemical vapor deposition for perovskite solar cells," Energy Environ. Sci., 13, 1997 (2020).[6] R. Heasley, L. M. Davis, D. Chua, C. M. Chang, and R. G. Gordon, "Vapor Deposition of Transparent, p-Type Cuprous Iodide Via a Two-Step Conversion Process," ACS Appl. Energy Mater., 1, 6953 (2018).[7] V. Gottschalch, S. Blaurock, G. Benndorf, J. Lenzner, M. Grundmann, and H. Krautscheid, "Copper iodide synthesized by iodization of Cu-films and deposited using MOCVD," J. Cryst. Growth, 471, 21 (2017).[8] C. M. Chang, L. M. Davis, E. K. Spear, and R. G. Gordon, "Chemical Vapor Deposition of Transparent, p-Type Cuprous Bromide Thin Films," Chem. Mater., 33, 1426 (2021).

The electronic structures and p-type performance of group IA and VA atoms in NiO: A first principles study

Transparent p-type semiconductors attract many researchers' interest because they are widely used in many devices such as solar cells, flat panel displays, and light emitting diodes and in the field of transparent electronics. NiO, as a potential transparent p-type semiconductor, has been studied in experiments. However, the ionization abilities of dopants, such as group IA and VA atoms, have not been confirmed yet. In this work, we utilize the first principles method and fully assess the performance of group IA and VA atom-doped NiO. Electronic structures show that group VA atoms substituting O are deep acceptors, while group IA atoms substituting Ni are optimal acceptors. Compared with the valence band maximum, the transition energy levels ε(0/−) of Li, Na, K, Rb, and Cs substituting Ni would converge to 0.087, 0.109, 0.15, 0.14, and 0.31 eV, respectively. Under an O-rich condition, compounds M2O (M = Li, Na, K, Rb, and Cs) are promising dopant sources for group IA atoms substituting Ni. In addition, group IA atoms substituting Ni are highly preferred over the interstitial doped configuration. We expect that this work can promote the understanding of the p-type conductivity of NiO and provide significant guidance for their applications in transparent electronics.

First-principles identification of VI + Cui defect cluster in cuprous iodide: origin of red light photoluminescence

The γ-phase cuprous iodide (CuI) emerges as a promising transparent p-type semiconductor for next-generation display technology because of its wide direct band gap, intrinsic p-type conductivity, and high carrier mobility. Two main peaks are observed in its photoluminescence (PL). One is short wavelength (410–430 nm) emission, which is well attributed to the electronic transitions at Cu vacancy, whereas the other long wavelength emission (680–720 nm) has not been fully understood. In this paper, through first-principles simulations, we investigate the formation energies and emission line shapes for various defects, and discover that the intrinsic point defect cluster is the source of the long wavelength emission. Our finding is further supported by the prediction that the defect concentration decreases dramatically as the chemical condition changes from Cu-rich to I-rich, explaining the significant reduction in the red light emission if CuI is annealed in abundant I environment.

Improved performance of transparent p-type conductors CuCrO2:Mg delafossite thin films through easy and low cost laser annealing

Films deposited on glass substrate by RF sputtering, were heat treated in air by a low power laser spot thanks to conventional photolithography machine, to obtain pure CuCr0.97Mg0.03O2 delafossite with an optical transmittance of 0.58 and a conductivity of 5.8S.cm−1. The Haacke’s figure of merit is improved to reach 2.07 × 10-7Ω−1. Laser annealing by a photolithography machine is thus very interesting for enhancing the p-type transparent conductor properties of such delafossite phases. A local annealing according to selected patterns could also be envisaged, opening up exciting prospects for fast and low cost making the most of these transparent p-type semiconductors.

Highly transparent and conductive p-type CuI films by optimized solid-iodination at room temperature

p-type CuI films with optimized optoelectronic performance were synthesized by solid-phase iodination of Cu3N precursor films at room temperature. The effects of the deposition power of Cu3N precursors on the structural, electrical, and optical properties of the CuI films were systematically investigated. X-ray diffraction results show that all the CuI films possess a zinc-blende structure. When the deposition power of Cu3N precursors was 140 W, the CuI films present a high transmittance above 84% in the visible region, due to their smaller root-mean-square roughness values of 9.23 nm. Moreover, these films also have a low resistivity of 1.63 × 10–2 Ω·cm and a boosted figure of merit of 140.7 MΩ−1. These results are significant achievements among various p-types TCOs, confirming the promising prospects of CuI as a p-type transparent semiconductor applied in transparent electronics.

Heavy-ion irradiation assisted modification of p-type transparent CuAlO2 films: Electrical, optical and thermoelectric properties

Heavy-ion (HI) irradiation is a unique approach to induce defects in semiconductor films. The ion irradiation leaves continuous columnar tracks to create various defects and reduce film density, modulating the thermoelectric properties of semiconductor films. As a p-type transparent oxide semiconductor (TOS), the as-synthesized CuAlO2 films were irradiated with different doses of Fe10+ ions at room temperature using the 320 kV High Voltage Platform, and then post-annealed to improve the microstructure and thermoelectric properties. The irradiated CuAlO2 films, with 15 × 1013 ions cm−2, can achieve an electrical conductivity of 0.14 S cm−1, which is about 200 times larger than the unirradiated counterparts. The Seebeck coefficient reaches up to 189.80 and 208.58 μV K−1 at room temperature and 600 K, respectively. Therefore, a high power factor (PF) of 9.15 μW m−1K−2 is rendered by the irradiated CuAlO2 films, whereas the unirradiated films are not detected in the given measurement range. The improved thermoelectric performance is mainly due to the increased copper vacancies in irradiated films without significantly reducing the crystallinity. The current work presents a promising strategy to improve the thermoelectric performance of semiconductor films.