Enhanced gain and detectivity of unipolar barrier solar blind avalanche photodetector via lattice and band engineering

Abstract

Ga2O3-based solar blind avalanche photodetectors exhibit low voltage operation, optical filter-free and monolithic integration of photodetector arrays, and therefore they are promising to be an alternative to the bulky and fragile photomultiplier tubes for weak signal detection in deep-ultraviolet region. Here, by deliberate lattice and band engineering, we construct an n-Barrier-n unipolar barrier avalanche photodetector consisting of β-Ga2O3/MgO/Nb:SrTiO3 heterostructure, in which the enlarged conduction band offsets fortify the reverse breakdown and suppress the dark current while the negligible valance band offsets faciliate minority carrier flow across the heterojunction. The developed devices exhibit record-high avalanche gain up to 5.9 × 105 and detectivity of 2.33 × 1016 Jones among the reported wafer-scale grown Ga2O3-based photodetectors, which are even comparable to the commercial photomultiplier tubes. These findings provide insights into precise manipulation of band alignment in avalanche photodetectors, and also offer exciting opportunities for further developing high-performance Ga2O3-based electronics and optoelectronics.

An enhanced ultrasensitive solar-blind UV photodetector based on an asymmetric Schottky junction designed with graphene/β-Ga2O3/Ag

“…No other diffraction peaks were detected, indicating that the prepared b-Ga 2 O 3 crystal is (100)-oriented single crystals. 27,28 The Raman spectra of the multilayer graphene film depicted in Fig. S2 (ESI †) illustrates high intensities of both the 2D and G peaks, with weak D peak associated with defects, which is indicative of a high quality sample with few defects.…”

Enhanced Responsivity and Optoelectronic Properties of Self-Powered Solar-Blind Ag2O/β-Ga2O3 Heterojunction-Based Photodetector with Ag:AZO Co-Sputtered Electrode

“…Figure 7 shows the parameters calculated from the I–V curve of the photodetector shown in Figure 5 based on the thermionic emission model [ 44 ]. The parameters were on-resistance (R on ), barrier potential ( φ B ), and ideality factor ( n ) based on thickness, and the thermionic emission model is as follows [ 45 ].…”

Overestimating the performance of photon detectors

“…As the solar noise background increases above 285 nm, there is a significant decrease in detectivity compared to SFL. The detectivity decreases exponentially from 9.5×10 17 Jones at 285 nm to about 10 12 Jones at 300 nm and approaches a plateau above 300 nm, where the natural solar spectrum begins to play a significant role.…”

“…Figure 1 shows the spectral detectivity of different types of photodetectors in the wavelength range from 0.1 μm to 2 μm [10][11][12][13][14][15][16][17][18][19][20], under conditions of an ambient background temperature of 290 K and a 2π steradian detector field of view (FOV). Ga O nBn Ref.…”