Properties of a photovoltaic detector based on an n-type GaN Schottky barrier

Abstract

In this article, we report on the characterization of a photovoltaic detector based on an n-type GaN Schottky barrier. We first present the photovoltaic responsivity above the gap. Its spectrum is explained by the combined effects of absorption and diffusion. The hole diffusion length is estimated to be in the 0.1 μm range with a numerical model. The photoresponse below the gap is also investigated and it is shown that the current generated by the internal photoemission is the major contribution to the photocurrent at reverse biases at 80 K. At room temperature, an additional component to the photocurrent is clearly demonstrated and identified. This extra current stems from the existence of traps. Several spectroscopy techniques are used to characterize those traps. The supplementary current emitted from the traps in the depletion region accounts for the spectral and the temporal behavior of the Schottky photodetector at room temperature.

Schottky barrier formation at the Au to rare earth doped GaN thin film interface

“…The European Physical Journal Applied Physics [28] I P E GaN 1.0 [29] I P E GaN 1.11 [24] I P E GaN 0.95 ± 0.04 [26] I P E GaN 0.97 ± 0.05 [27] I P E calculated as 1.33 ± 0.1 eV via (4). The same methods and calculations described above yielded Schottky barrier heights of 1.64 ± 0.1 eV and 1.68 ± 0.1 eV for Er:GaN and Yb:GaN, respectively.…”

“…Surface alloying can occur [14] and a large range of experimentally measured Schottky barrier heights has been reported (0.76-1.40 eV) at the Au to n-type GaN interface [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29], using photoemission spectroscopy (PES), current-voltage (I-V) and capacitance voltage (C-V) characteristics, and internal photoemission [30]. However, the generally accepted value is about 1.08 eV [31].…”

Effects of phase separation and decomposition on the minority carrier diffusion length in AlxGa1−xN films

“…2 The diffusion length of carriers is a material parameter that greatly influences the performance of electronic and opto-electronic devices. In the case of GaN, only few papers [3][4][5][6][7] report diffusion length data measured by different techniques, in the range from 0.1 to 3.4 m depending on the carrier concentration and crystal quality. Electron beam induced current ͑EBIC͒ in the scanning electron microscope ͑SEM͒ is an established technique to measure the diffusion length of minority carriers in semiconductors.…”

p-GaN-i-GaN/AlGaN multiple-quantum well n-AlGaN back-illuminated ultraviolet detectors

“…1 The III-V nitride alloys are ideal candidates for these applications because of their large direct bandgaps, which cover the range from 3.4 eV (GaN) to 6.2 eV (AlN). Over the past decade, there have been several reports on GaN-AlGaN-based most common detector types, such as photoconductors, 2,3 p-n junction, 4-6 p-i-n, 7-10 Schottky barrier, [11][12][13][14] and metalsemiconductor metal. 15,16 Peak responsivities and corresponding quantum efficiencies are scattering in a wide range, depending on the device design and material qualities.…”