Balancing the Transmittance and Carrier‐Collection Ability of Ag Nanowire Networks for High‐Performance Self‐Powered Ga₂O₃ Schottky Photodiode

Abstract

Self‐powered solar‐blind photodiodes with convenient operation, easy fabrication, and weak‐light sensitivity, are highly desired in environmental monitoring and deep space exploration. Ga2O3 with its bandgap directly corresponding to solar‐blind waveband is a promising candidate material for solar‐blind photodetection. However, ever‐reported self‐powered Ga2O3 photodiodes suffer unsatisfactory photoresponse performance, owing to unideal interface and electrode transmittance. Here, Ag nanowire (AgNW) networks with excellent solar‐blind ultraviolet transmittance are introduced to form self‐powered AgNW–Ga2O3 photodiodes with sharp Schottky interfaces. The tradeoff between solar‐blind ultraviolet transmittance and carrier‐collection ability of the sparse AgNW network is systematically studied and the AgNW density is optimized for the best photoresponse. Expansion of depletion region outwards the AgNW–Ga2O3 contact and the field crowding effect facilitate the high photoresponse. As a result, the champion AgNW–Ga2O3 Schottky photodiode exhibits excellent sensitivity for weak‐light detection, including considerable responsivity of 14.8 mA W–1, ultrahigh photo‐to‐dark‐current ratio above 1.2 × 105, high rejection ratio (R254 nm/R365 nm) of 2.6 × 103, and fast response speed (rise/decay time of 20/24 ms) under self‐powered mode. Balancing the transmittance and carrier‐collection ability of elaborate electrode provides an alternative strategy to achieve high‐performance self‐powered Ga2O3 photodetectors for future weak‐light‐sensitive optoelectronic systems.

Unintentional doping effect in Si-doped MOCVD β-Ga2O3 films: Shallow donor states

“…β-Ga 2 O 3 is an important candidate semiconductor material for next-generation power electronic devices and solar-blind ultraviolet photodetectors, due to its ultra-wide bandgap, high critical electric breakdown field, and large Baliga's figure of merit [1-4]. In the past few years, high-performance β-Ga 2 O 3 -based devices including Schottky barrier diode (SBD) [5,6], pn diode [7,8], metal-oxide-semiconductor field-effect transistor (MOSFET) [9,10], and photodetector [11][12][13][14][15][16] have been quickly demonstrated, in which high-quality epitaxial films are of crucial importance [6,7,9]. One of the most important methods to obtain epitaxial β-Ga 2 O 3 films is metalorganic chemical vapor deposition (MOCVD), thanks to its fast growth rate, large area homogeneity, and superb film quality [17][18][19][20].…”

Aqueous‐Printed Ga2O3 Films for High‐Performance Flexible and Heat‐Resistant Deep Ultraviolet Photodetector and Array

“…The strong Raman peak at 1052 cm −1 in Figure 2a of the S100 film represents the existence of NO 3 − , [33] which disappeared after 350 °C baking. Based on the results of Raman and XRD spectra of the S900 film, [35][36][37] the final products after 900 °C annealing are proved to be high-quality crystalline Ga 2 O 3 films, as labeled in Figure 2a,b. Referring to previous reports, the evolution from the S100 film to the S900 film should have undergone the following hydrolysis and dehydration reactions.…”

A Spiro-MeOTAD/Ga2O3/Si p-i-n Junction Featuring Enhanced Self-Powered Solar-Blind Sensing via Balancing Absorption of Photons and Separation of Photogenerated Carriers

“…In the case of the D3 device, except as the more photons go through the spiro layer, the carrier separation efficiency improved due to the increased thickness of the spiro. That is, the high photocurrent of the D3 device is attributed to more photon absorption and the stronger photoexcited e–h pair separation ability due to the reasonable thickness of the spiro layer …”

“…That is, the high photocurrent of the D3 device is attributed to more photon absorption and the stronger photoexcited e−h pair separation ability due to the reasonable thickness of the spiro layer. 17 To further elucidate the influence of the thickness of spiro on our devices, we performed transient photocurrent measurements at zero bias. The real-time photoresponse of the asprepared devices with various spiro thicknesses at 0 V further confirms the aforementioned explanation, as shown in Figure 3d.…”

“…With the change in spiro thickness, the transmittance of the spiro, the open circuit voltage (V oc ), and the short circuit current (I sc ) of the PD can be adjusted. 17 Based on the balancing of the efficiency of SBUV photon transmittance, carrier generation, and separation ability by varying the thicknesses of spiro, we demonstrated an optimized device with a superhigh photoresponse characteristics, including a responsivity of 192 mA/W and EQE of 93.6% at zero bias. The outstanding photoresponse performance of our PD is superior or comparable to the works reported previously.…”