Enhancing Performance of GaAs Photodiodes via Monolithic Integration of Self‐Formed Graphene Quantum Dots and Antireflection Surface Texturing

Abstract

III–V semiconductor‐based photodiodes with graphene incorporated have been studied in recent years due to the attractive optoelectronic properties of graphene, including optical transparency and enhanced photoresponsivity. The photoresponsivity can be further improved by converting the semiconductor surface into a 3D antireflection (AR) structure. However, difficulties in transferring graphene on top of structured surfaces degrade the interfacial quality and limit their photoresponsivity. Herein, a high‐performance GaAs photodiode structure with self‐embedded graphene quantum dot (GQD) and simultaneously formed periodic AR 3D surface texturing is reported, all produced by a one‐step wet etching process in a solution of hydrogen fluoride (HF) and potassium permanganate (KMnO4) using graphene as a transparent mask. Compared with the planar counterpart without graphene, the photodiodes demonstrated here show an enhancement of photocurrent by 22 times, photoresponsivity by 25 times, and normalized photocurrent to dark current ratio by approximately two orders of magnitude. The improved photoresponsivity of 9.31 mA W−1 is attributed to the increased absorption from AR texturing and the enhanced heterointerface carrier transfer from GQDs to GaAs. This simple, clean yet effective method enables the monolithic incorporation of graphene and graphene‐derived materials on 3D semiconductor structures for applications across a wide range of wavelengths.

Distinct UV–Visible Responsivity Enhancement of GaAs Photodetectors via Monolithic Integration of Antireflective Nanopillar Structure and UV Absorbing IGZO Layer

“…For example, Namiki et al. [ 21 ] fabricated GaAs nanogrooves which exhibited distinctly reduced reflectance from 400 to 1000 nm wavelength. However, this photodetector was only characterized under 532 nm visible illumination and its performance enhancement in a broadband UV–visible range was not reported.…”

“…[20] Although some of these works on surface texturing demonstrated low UV-visible reflection below 5%, none of them have systematically studied an implication of the textured antireflection layer in GaAs photodetectors and their performance enhancement in a broadband UV-visible range. For example, Namiki et al [21] fabricated GaAs nanogrooves which exhibited distinctly reduced reflectance from 400 to 1000 nm wavelength. However, this photodetector was only characterized under 532 nm visible illumination and its performance enhancement in a broadband UV-visible range was not reported.…”

Gallium-V antireflective nanostructures by metal-assisted chemical etching for photodetector application

“…In terms of PD applications, Ishimori et al [93] fabricated GaAlAs subwavelength gating by dry etching and the photodiode based on it exhibited improved short-circuit current and open-circuit voltage when tested under 780 nm visible light. Also, by MacEtch, Namiki et al [94] employed monolayer graphene as catalyst to fabricate antireflective surface texturing on GaAs, with which a two orders of magnitude improvement of responsivity was observed under 532 nm visible illumination. For GaAs-based UV PDs, despite studies are relatively scarce, there are still reports employing surface antireflection texturing, which has been proven effective in enhancing responsivity in GaAs Schottky UV PDs [82][83] .…”

“…Although absolute responsivity in the visible range is lower than n-GaAs based PDs because of the highly resistive nature of the GaAs substrates, the integration scheme of nanopillar antireflective texturing and IGZO layer is a feasible way to distinctly enhance responsivity of GaAs PD. UID GaAs MSM N/A 0.364 (@ 532 nm) Namiki [94] Graphene/n-GaAs nanowire N/A 1.54 (@ 532 nm) Wu [171] MLG/n-GaAs nanocone N/A 1.73 (@ 850 nm) Luo [163] CNT/n-GaAs N/A 230 (@ 532 nm) Huo [172] CuI/IGZO 0.6 (@ 365 nm) N/A Yamada [173] Au/IGZO/Au 2.3 (@365 nm) N/A Kumaresan [174] FDTD simulation was used in order to investigate the mechanism of the light absorption enhancement by nanopillar structure and IGZO. Figure 18 shows the simulated electric field distribution of the planar and nanopillar in the same wavelength range.…”