Laser-Induced Doping of CdTe Crystals in Different Environments

Gnatyuk, V. A.; Levytskyi, S. N.; Vlasenko, A. I.; Aoki, Toru

doi:10.4028/www.scientific.net/amr.222.32

Cited by 20 publications

(24 citation statements)

References 9 publications

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“…The whole surface area of the CdTe crystal pre-coated with an In film was entirely and uniformly irradiated with nanosecond laser pulses at room temperature ( Figure 7 b). It was shown that distilled water environment was the optimal ambient condition for such treatment [ 55 ]. A KrF excimer laser, emitting single pulses with a wavelength of 248 nm and duration of 20 ns, was a pulsed radiation source.…”

Section: Capabilities Of Cdte-based X/γ-ray Detectors With An In Contact Treated By Laser Pulse Radiationmentioning

confidence: 99%

“…The use of a relatively thick In electrode (0.3–0.5 µm), which also served as an dopant film, made it possible to ensure laser-induced doping without heating the underlying bulk In region and CdTe crystal that avoided a heat-induced deterioration of the structure and properties of the semiconductor. Despite the fact that absorption of laser radiation occurred in a thin (tens of nanometers) In surface layer, the thin semiconductor region under the In/CdTe interface was heavily doped with In atoms [ 55 , 56 ]. It was supposed that In/CdTe/Au diode structures with an In doped CdTe nano-layer and built-in p-n junction were obtained as a result of laser-stimulated modification of the defect structure and solid-phase doping in the deep-seated CdTe region.…”

Section: Capabilities Of Cdte-based X/γ-ray Detectors With An In Contact Treated By Laser Pulse Radiationmentioning

confidence: 99%

“…Rapid expansion of the laser-heated In surface region and plasma recoil momentum resulted in generation of high-amplitude stress waves which were transformed to a high pressure shock wave [ 57 ]. Laser-induced stress and shock waves propagated through the In film and entered the CdTe crystal involving In dopant atoms [ 55 , 56 ]. Laser-stimulated penetration of high-concentration In dopants into the thin semiconductor region near the In-CdTe interface was due to essential elastic stress gradients, generation of stress and shock waves, and superfast diffusion of In atoms due to barodiffusion [ 56 ].…”

Section: Capabilities Of Cdte-based X/γ-ray Detectors With An In Contact Treated By Laser Pulse Radiationmentioning

confidence: 99%

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CdTe X/γ-ray Detectors with Different Contact Materials

Gnatyuk

Maslyanchuk

Solovan

et al. 2021

Sensors

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Different contact materials and optimization of techniques of their depositions expand the possibilities to obtain high performance room temperature CdTe-based X/γ-ray detectors. The heterostructures with ohmic (MoOx) and Schottky (MoOx, TiOx, TiN, and In) contacts, created by DC reactive magnetron sputtering and vacuum thermal evaporation, as well as In/CdTe/Au diodes with a p-n junction, formed by laser-induced doping, have been developed and investigated. Depending on the surface pre-treatment of semi-insulating p-CdTe crystals, the deposition of a MoOx film formed either ohmic or Schottky contacts. Based on the calculations and I‑V characteristics of the Mo-MoOx/р-CdTe/MoOx-Mo, In/р-CdTe/MoOx-Mo, Ti-TiOx/р-CdTe/MoOx-Mo, and Ti-TiN/р-CdTe/MoOx-Mo Schottky-diode detectors, the current transport processes were described in the models of the carrier generation–recombination within the space-charge region (SCR) at low bias, and space-charge limited current incorporating the Poole–Frenkel effect at higher voltages, respectively. The energies of generation–recombination centers, density of trapping centers, and effective carrier lifetimes were determined. Nanosecond laser irradiation of the In electrode, pre-deposited on the p-CdTe crystals, resulted in extending the voltage range, corresponding to the carrier generation–recombination in the SCR in the I‑V characteristics of the In/CdTe/Au diodes. Such In/CdTe/Au p-n junction diode detectors demonstrated high energy resolutions (7%@59.5 keV, 4%@122 keV, and 1.6%@662 keV).

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Section: Capabilities Of Cdte-based X/γ-ray Detectors With An In Contact Treated By Laser Pulse Radiationmentioning

confidence: 99%

Section: Capabilities Of Cdte-based X/γ-ray Detectors With An In Contact Treated By Laser Pulse Radiationmentioning

confidence: 99%

Section: Capabilities Of Cdte-based X/γ-ray Detectors With An In Contact Treated By Laser Pulse Radiationmentioning

confidence: 99%

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CdTe X/γ-ray Detectors with Different Contact Materials

Gnatyuk

Maslyanchuk

Solovan

et al. 2021

Sensors

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“…Laser processing of CdTe has been successfully used to modify the structure and properties of surface nano-layers and change different characteristics of the semiconductor. Of particular interest is application the laser assisted doping technique to suppress the dopant self-compensation mechanism, and reach introducing and efficient electrical activation of In atoms in CdTe [5][6][7][8][9][10]. We have continued development and optimization the methods of chemical surface processing of CdTe crystals, laser induced doping technique for creation of a built-in p-n junction by nanosecond laser irradiation of the CdTe crystals precoated with a relatively thick In film which serves both as an n-type dopant source and electrical contact (electrode) after the doping and deposition of the second electrode [7][8][9][10].The formation of a surface nano-layer highly-doped with In in semi-insulating detector-grade p-like CdTe crystals and creation of In/CdTe/Au diodes with a shallow and sharp p-n junction has been studied and mechanism of laser-induced doping is analyzed.…”

Section: Introductionmentioning

confidence: 99%

Modeling of diffusion motion of In nanoparticles in a CdTe crystal during laser-induced doping

Levytskyi

Zhao

Cao

et al. 2021

Phys. Chem. Solid St.

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In order to solve the problem of the ohmic contact between the crystal surface and the metal electrode in the manufacturing process of the X/γ-ray detector, this paper uses a laser to probe the doping process of In/CdTe crystals in different media. In this experiment, the Traveling Heater Method (THM) is used to obtain CdTe(111) crystals that meet the requirements (ρ >109Ω∙cm). In and Au materials are respectively coated on the surface of the crystal sample by the vacuum thermal evaporation method to obtain the crystal sample meeting the requirements. The high-resistance p-type CdTe crystal of a relatively thick In film is irradiated with nanosecond laser pulses, the In film is used as an n-type doping source and as an electrode after laser irradiation.

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“…The use of another etching solution also results in contamination of the crystal surface with chemical reaction products. Recently, pulsed laser irradiation has been successfully used for surface processing of CdTe crystals [6][7][8][9][10] . However, in this case the laser-treated surface of CdTe crystal as becomes enriched with Te 10 .…”

Section: Introductionmentioning

confidence: 99%

Photoluminescence and absorption properties of the surface functional layer of CdTe crystals

Gnatyuk

Поперенко

Yurgelevych

et al. 2012

Hard X-Ray, Gamma-Ray, and Neutron Detector Physics XIV

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Photoluminescence and optical properties of the surface functional layer of detector-grade Cl-compensated semiconductor CdTe(111) single crystals modified by chemical etching and nanosecond laser processing have been studied. A bromine-methanol solution was used for polishing etching and nanosecond pulses of the second harmonic of YAG:Nd laser was applied as a radiation source. The photoluminescence spectra were excited at 80 K by an argon-ion laser with wavelength of 488 nm. The intrinsic emission band at 1.56 eV and broad defect band peaked at 1.45 eV were observed in the spectra before and after chemical and laser processing of CdTe crystals. The emission between 1.4-1.5 eV was associated with carrier recombination at defects in the surface region, so called the band of surface states. The optical parameters were determined using an ellipsometer with laser wavelength of 632.8 nm. Refraction n and absorption k indices were calculated within model of a homogeneous absorbing surface layer upon an absorbing substrate. An increase in n and k was observed at laser irradiation with energy density near or higher than the CdTe melting threshold that was attributed to an increase in volume fraction of Te in the surface region of the crystal. A decrease in the emission intensity at 1.45 eV was evidence of a reduction of the surface impurity contribution to the spectrum as a result of chemical etching. A rise of this band after irradiation was due of formation of point defects and dislocations in a surface layer of the crystal.

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Laser-Induced Doping of CdTe Crystals in Different Environments

Cited by 20 publications

References 9 publications

CdTe X/γ-ray Detectors with Different Contact Materials

CdTe X/γ-ray Detectors with Different Contact Materials

Modeling of diffusion motion of In nanoparticles in a CdTe crystal during laser-induced doping

Photoluminescence and absorption properties of the surface functional layer of CdTe crystals

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