A high figure‐of‐merit UV‐C solar‐blind photodetector (PD) fabricated from thin‐film beta‐gallium oxide (β‐Ga2O3) grown on
In this study, Si/β‐Ga2O3solar‐blind photodetectors (PDs) have been demonstrated via micro‐transfer printing of a single crystalline Si pillar on β‐Ga2O3. Unlike other previous approaches for β‐Ga2O3based heterojunction, this new single crystalline p‐n Si/β‐Ga2O3heterojunction has a particle‐free heterointerface and does not show any sign of internal strain after the heterogeneous integration that is confirmed by Raman spectroscopy. As a result, PDs exhibit extremely high photoresponsivity (748 A W−1), quantum efficiency (3.67 × 105%), and UV/visible rejection ratio (≈105) under UV light illumination. This result is believed to provide a viable route for the realization of high‐performance solar‐blind photodetection systems, which form some of the most indispensable and important components in high‐performance next‐generation security, biomedical, and environmental monitoring systems. Also, the unique heterogeneous integration method allows us to realize a variety of β‐Ga2O3based heterostructures that can further enhance the optical performances of β‐Ga2O3based PDs.
more » « less- Award ID(s):
- 1809077
- PAR ID:
- 10363826
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials Technologies
- Volume:
- 6
- Issue:
- 6
- ISSN:
- 2365-709X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
n ‐Si substrates by plasma‐assisted molecular beam epitaxy is demonstrated. Film growth sequences for nucleation of Ga2O3on (100)‐ and (111)‐oriented Si substrates are developed, and the influence of crucial growth parameters is systematically investigated, namely, substrate temperature, oxygen flow rate, and plasma power on the functional properties of the PDs. The PDs show an ultra‐high responsivity of 837 A W−1and a fast ON/OFF time below 4 ms at −5 V. In addition, they display strong rectifying properties and a sharp cutoff below 280 nm with the average responsivities between 10 and 80 A W−1, a detectivity on the order of 1010 Jones, and rise/fall times between 4 and 500 ms. High photoconductive gain is likely to be due to the mid‐bandgap donor/acceptor defect levels, including oxygen vacancies in the form of self‐trapped holes. It is demonstrated that these defect levels can be modified by controlling the growth conditions, thereby allowing for tailoring of the PD characteristics for specific applications. The methodology represents a cost‐effective solution over homoepitaxial approaches, with characteristics that meet or exceed those reported previously, offering new possibilities for on‐wafer integration with Si opto‐electronics. -
more » « less
Abstract With the astonishing advancement of present technology and increasing energy consumption, there is an ever‐increasing demand for energy‐efficient multifunctional sensors or transducers based on low‐cost, eco‐friendly material systems. In this context, self‐assembled vertically aligned
β ‐Ga2−x Wx O3nanocomposite (GWO‐VAN) architecture‐assisted self‐biased solar‐blind UV photodetection on a silicon platform, which is the heart of traditional electronics is presented. Utilizing precisely controlled growth parameters, the formation of W‐enriched verticalβ ‐Ga2−x Wx O3nanocolumns embedded into the W‐deficientβ ‐Ga2−x Wx O3matrix is reached. Detailed structural and morphological analyses evidently confirm the presence ofβ ‐Ga2−x Wx O3nanocomposite with a high structural and chemical quality. Furthermore, absorption and photoluminescence spectroscopy explains photo‐absorption dynamics and the recombination through possible donor–acceptor energy states. The proposed GWO‐VAN framework facilitates evenly dispersed nanoregions with asymmetric donor energy state distribution and thus forms build‐in potential at the verticalβ ‐Ga2−x Wx O3interfaces. As a result, the overall heterostructure evinces photovoltaic nature under the UV irradiation. A responsivity of ≈30 A/W is observed with an ultrafast response time (≈350 µs) under transient triggering conditions. Corresponding detectivity and external quantum efficiency are 7.9 × 1012Jones and 1.4 × 104%, respectively. It is believed that, while this is the first report exploiting GWO‐VAN architecture to manifest self‐biased solar‐blind UV photodetection, the implication of the approach is enormous in designing electronics for extreme environment functionality and has immense potential to demonstrate drastic improvement in low‐cost UV photodetector technology. -
null (Ed.)This paper reports the fabrication of β-Ga 2 O 3 nanomembrane (NM) based flexible photodetectors (PDs) and the investigation of their optoelectrical properties under bending conditions. Flexible β-Ga 2 O 3 NM PDs exhibited reliable solar-blind photo-detection under bending conditions. Interestingly, a slight shifting in wavelength of the maximum solar-blind photo-current was observed under the bending condition. To investigate the reason for this peak shifting, the optical properties of β-Ga 2 O 3 NMs under different strain conditions were measured, which revealed changes in the refractive index, extinction coefficient and bandgap of strained β-Ga 2 O 3 NMs due to the presence of nano-sized cracks in the β-Ga 2 O 3 NMs. The results of a multiphysics simulation and a density-functional theory calculation for strained β-Ga 2 O 3 NMs showed that the conduction band minimum and the valence band maximum states were shifted nearly linearly with the applied uniaxial strain, which caused changes in the optical properties of the β-Ga 2 O 3 NM. We also found that nano-gaps in the β-Ga 2 O 3 NM play a crucial role in enhancing the photoresponsivity of the β-Ga 2 O 3 NM PD under bending conditions due to the secondary light absorption caused by reflected light from the nano-gap surfaces. Therefore, this research provides a viable route to realize high-performance flexible photodetectors, which are one of the indispensable components in future flexible sensor systems.more » « less
-
more » « less
Abstract Here, high power flexible Schottky barrier diodes (SBDs) are demonstrated on a plastic substrate using single crystalline β‐Ga2O3nanomembranes (NMs). In order to realize flexible high power β‐Ga2O3SBDs, sub‐micron thick freestanding β‐Ga2O3NMs are created from a bulk β‐Ga2O3substrate and transfer‐printed onto the plastic substrate via a microtransfer printing method. It is revealed that the material property of β‐Ga2O3NMs such as crystal structure, electron affinity, and bandgap remains unchanged compared with its bulk properties. Flexible β‐Ga2O3SBDs exhibit the record high critical breakdown field strength (
E c) of 1.2 MV cm−1in the flat condition and 1.07 MV cm−1ofE cunder the bending condition. Overall, flexible β‐Ga2O3SBDs offer great promise for future flexible energy convergence systems and are expected to provide a much larger and more versatile platform to address a broader range of high‐performance flexible applications. -
Abstract In this paper, transient delayed rise and fall times for beta gallium oxide ( β -Ga 2 O 3 ) nanomembrane (NM) Schottky barrier diodes (SBDs) formed on four different substrates (diamond, Si, sapphire, and polyimide) were measured using a sub-micron second resolution time-resolved electrical measurement system under different temperature conditions. The devices exhibited noticeably less-delayed turn on/turn off transient time when β -Ga 2 O 3 NM SBDs were built on a high thermal conductive (high- k ) substrate. Furthermore, a relationship between the β -Ga 2 O 3 NM thicknesses under different temperature conditions and their transient characteristics were systematically investigated and verified it using a multiphysics simulator. Overall, our results revealed the impact of various substrates with different thermal properties and different β -Ga 2 O 3 NM thicknesses on the performance of β -Ga 2 O 3 NM-based devices. Thus, the high- k substrate integration strategy will help design future β -Ga 2 O 3 -based devices by maximizing heat dissipation from the β -Ga 2 O 3 layer.more » « less
