Modeling AlGaN p-i-n photodiodes

Doklady BGUIR ◽  
2022 ◽  
Vol 19 (8) ◽  
pp. 50-57
Author(s):  
N. N. Vorsin ◽  
A. A. Gladyshchu ◽  
T. L. Kushner ◽  
N. P. Tarasiuk ◽  
S. V. Chugunov ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Band Gap ◽  
Layer Thickness ◽  
Transition Matrix ◽  
Carrier Lifetime ◽  
Relevant Literature ◽  
Radiation Absorption ◽  
Comsol Multiphysics ◽  
Spontaneous Recombination ◽  
Peak Sensitivity

Ternary AlGaN alloys with a band gap of 3.4 to 6.2 eV are very promising for photodetectors in the UV wavelength range. Using the COMSOL MULTIPHYSICS software based on AlGaN, a p-i-n photodiode model was developed, including its I–V characteristic, spectral sensitivity of the received radiation, absorption coefficient as a function of the aluminum fraction and the depletion layer thickness. To calculate the process of interaction of a semiconductor with EM radiation, we used a model based on the use of an element of the transition matrix through the carrier lifetime during spontaneous recombination. In this case, the peak sensitivity of the photodiode is from 0.08 to 0.18 A/W at wavelengths of 0.2–0.33 µm. This is in line with experimental results taken from the relevant literature.

scholarly journals The Band-Gap Studies of Short-Period CdO/MgO Superlattices

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Ewa Przeździecka ◽  
P. Strąk ◽  
A. Wierzbicka ◽  
A. Adhikari ◽  
A. Lysak ◽  
...  
Keyword(s):  
Band Gap ◽  
Layer Thickness ◽  
Energy Gap ◽  
Band Gaps ◽  
Short Period ◽  
Wide Range ◽  
Salt Structure ◽  
Short Period Superlattices ◽  
Direct Band ◽  
Sublayer Thickness

AbstractTrends in the behavior of band gaps in short-period superlattices (SLs) composed of CdO and MgO layers were analyzed experimentally and theoretically for several thicknesses of CdO sublayers. The optical properties of the SLs were investigated by means of transmittance measurements at room temperature in the wavelength range 200–700 nm. The direct band gap of {CdO/MgO} SLs were tuned from 2.6 to 6 eV by varying the thickness of CdO from 1 to 12 monolayers while maintaining the same MgO layer thickness of 4 monolayers. Obtained values of direct and indirect band gaps are higher than those theoretically calculated by an ab initio method, but follow the same trend. X-ray measurements confirmed the presence of a rock salt structure in the SLs. Two oriented structures (111 and 100) grown on c- and r-oriented sapphire substrates were obtained. The measured lattice parameters increase with CdO layer thickness, and the experimental data are in agreement with the calculated results. This new kind of SL structure may be suitable for use in visible, UV and deep UV optoelectronics, especially because the energy gap can be precisely controlled over a wide range by modulating the sublayer thickness in the superlattices.

scholarly journals Synthesis and Characterisation of Thin Films of Bismuth Triiodide for Semiconductor Radiation Detectors

2014 ◽  
Vol 2014 ◽  
pp. 1-3 ◽  
Author(s):  
Alka Garg ◽  
Monika Tomar ◽  
Vinay Gupta
Keyword(s):  
Thin Films ◽  
Absorption Coefficient ◽  
Room Temperature ◽  
Active Material ◽  
Visible Region ◽  
Radiation Detectors ◽  
Radiation Absorption ◽  
X Rays ◽  
X Ray ◽  
Bismuth Iodide

Bismuth iodide is a potentially active material for room temperature radiation detector, as it is well reported in the literature that it has both wide energy band gap and high atomic absorption coefficient. Crystalline films of high atomic number and high radiation absorption coefficient can absorb the X-rays and convert them directly into electrical charges which can be read by imaging devices. Therefore, it was proposed to grow thin films of Bismuth iodide on glass substrate using thermal evaporation technique in vacuum to avoid the inclusion of impurities in the films. The structural studies of the films were carried out using XRD and optical absorption measurement was carried out in the UV/VIS region using spectrophotometer. All Bismuth iodide films grown at room temperature are polycrystalline and show X-ray diffraction peaks at angles reported in research papers. The optical transmission spectra of BiI3 films show a high transmission of about 80% in visible region with a sharp fall near the fundamental absorption at 650 nm. Resistivity of the as-grown film was found to be around 1012 ohm-cm suitable value for X-ray detection application. Films were subjected to scanning electron microscopy to study the growth features of both as-grown and annealed films.

LASER-INDUCED MULTIPHOTON PHOTOCONDUCTIVITY IN DIRECT AND INDIRECT BAND GAP CRYSTALS USING Z-SCAN TECHNIQUE

2009 ◽  
Vol 23 (23) ◽  
pp. 2783-2789 ◽  
Author(s):  
ARUN GAUR ◽  
D. K. SHARMA ◽  
K. S. SINGH ◽  
NAGESHWAR SINGH
Keyword(s):  
Absorption Coefficient ◽  
Band Gap ◽  
Laser Pulses ◽  
Beam Waist ◽  
Photon Absorption ◽  
Nanosecond Laser ◽  
Direct Band Gap ◽  
Direct Band ◽  
Nanosecond Laser Pulses ◽  
Indirect Band Gap

Nanosecond laser pulses have employed the photoconductive Z-scan technique. Photoconductivity traces measured by moving the sample across the laser beam waist were used for measuring two and three-photon absorption processes. The value of the three-photon absorption coefficient β3=9.6×10-10 cm 3/ GW 2 in the case of direct, and 8.96×10-12 cm 3/ GW 2 and 5.0×10-12 cm 3/ GW 2 in the case of indirect band gap crystals have been estimated from a comparison of traces measured by exciting the sample with the first and second harmonics of Nd : YAG laser. The low value of β3 in the case of indirect band gap crystals compared to direct band gap crystals is attributed to phonon-assisted transitions.

scholarly journals Absorption Coefficient and Refractive Index of GaN, AlN and AlGaN Alloys

1999 ◽  
Vol 4 (S1) ◽  
pp. 502-507 ◽  
Author(s):  
J. F. Muth ◽  
J. D. Brown ◽  
M. A. L. Johnson ◽  
Zhonghai Yu ◽  
R. M. Kolbas ◽  
...  
Keyword(s):  
Refractive Index ◽  
Absorption Coefficient ◽  
Band Gap ◽  
Optoelectronic Devices ◽  
Optical Absorption Coefficient ◽  
Solar Blind ◽  
Single Crystal Films ◽  
Crystal Films ◽  
Transmission Measurements ◽  
Reflectance Measurements

The design of optoelectronic devices fabricated from III-nitride materials is aided by knowledge of the refractive index and absorption coefficient of these materials. The optical properties of GaN, AlN and AlGaN grown by MOVPE on sapphire substrates were investigated by means of transmittance and reflectance measurements. Thin (less than 0.5 μm) single crystal films were employed to insure that transmission measurements could be obtained well above the optical band gap. The influence of alloy broadening on the absorption edge was investigated by using a series of AlGaN alloy samples with a range of Al compositions. The optical absorption coefficient above the band gap was obtained for AlGaN having up to 38% Al composition. The refractive index below the band gap was determined for the same series of samples. These properties provide information critical to the optimal design of solar blind detectors or other optoelectronic devices.

A DFT study of the electronic, optical and topological properties of free and biaxially strained CuIn1−xAlxSe2

2019 ◽  
Vol 7 (19) ◽  
pp. 5803-5815 ◽  
Author(s):  
Pingping Jiang ◽  
Pascal Boulet ◽  
Marie-Christine Record
Keyword(s):  
Thin Films ◽  
Absorption Coefficient ◽  
Band Gap ◽  
Conversion Efficiency ◽  
Dft Study ◽  
Topological Properties

Among the CuIn1−xAlxSe2 alloys, that with x = 0.25 is the optimal one in terms of band gap and conversion efficiency. Its absorption coefficient is highly modified under biaxial strains that occur in thin films.

Carrier Lifetimes in 4H-SiC Epitaxial Layers on the C-Face Enhanced by Carbon Implantation

2018 ◽  
Vol 924 ◽  
pp. 432-435 ◽  
Author(s):  
Mitsuhiro Kushibe ◽  
Johji Nishio ◽  
Ryosuke Iijima ◽  
Akira Miyasaka ◽  
Hirokuni Asamizu ◽  
...  
Keyword(s):  
Carrier Concentration ◽  
Layer Thickness ◽  
Epitaxial Layer ◽  
Carrier Lifetime ◽  
Epitaxial Layers ◽  
Carrier Lifetimes ◽  
Post Annealing

Carrier lifetime in low carrier concentration 4H-SiC epitaxial layers grown on the C-face was enhanced by using carbon implantation and post annealing. The measured carrier lifetime increased with the thickness of the epitaxial layer and was 11.4 µs for the 150 µm thick epitaxial layer. The internal carrier lifetime was estimated as 21 µs from the dependence of the measured carrier lifetime on the epitaxial layer thickness. This value is almost comparable to the reported values of the internal carrier lifetime for the layers grown on the Si-face.

Absorption Coefficient and Refractive Index of GaN, AIN and AlGaN Alloys

1998 ◽  
Vol 537 ◽  
Author(s):  
J. F. Muth ◽  
J. D. Brown ◽  
M. A. L. Johnson ◽  
Zhonghai Yu ◽  
R. M. Kolbas ◽  
...  
Keyword(s):  
Refractive Index ◽  
Absorption Coefficient ◽  
Band Gap ◽  
Optoelectronic Devices ◽  
Optical Absorption Coefficient ◽  
Solar Blind ◽  
Single Crystal Films ◽  
Crystal Films ◽  
Transmission Measurements ◽  
Reflectance Measurements

AbstractThe design of optoelectronic devices fabricated from III-nitride materials is aided by knowledge of the refractive index and absorption coefficient of these materials. The optical properties of GaN, AIN and A1GaN grown by MOVPE on sapphire substrates were investigated by means of transmittance and reflectance measurements. Thin (less than 0.5 μm) single crystal films were employed to insure that transmission measurements could be obtained well above the optical band gap. The influence of alloy broadening on the absorption edge was investigated by using a series of AlGaN alloy samples with a range of Al compositions. The optical absorption coefficient above the band gap was obtained for AIGaN having up to 38% Al composition. The refractive index below the band gap was determined for the same series of samples. These properties provide information critical to the optimal design of solar blind detectors or other optoelectronic devices.

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