RU2510101C2 - Photosensitive structure and selective photodetector based thereon - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: in a photosensitive structure, which is a multilayer semiconductor heterostructure which is sensitive to terahertz radiation at effective photocurrent temperature, said heterostructure having a quantum well in form of a layer of a narrow-bandgap solid solution containing Hg and Te and enclosed between barrier layers of a wide-bandgap three-component solid solution of Cd_yHg_1-yTe, where y is a value preferably in the range from 65% to 72%, the narrow-bandgap quantum well is formed from a three-component solid solution of Hg_1-xCd_xTe with content of Cd defined by a value x in the range from 4% to 12%, wherein the width of the quantum well is selected for the given terahertz frequency subrange of the received radiation at temperature of 4.2 K or 77 K depending on content of Cd in accordance with table 1 given in the claim. When the disclosed photosensitive structure is made as a desired terahertz photodetector - selective photodetector, in the latter, having a terahertz radiation sensitive photodetector line, which is in form of saeries-arranged areas of a multilayer semiconductor heterostructure having effective photosensitivity in different terahertz subranges at temperature of 4.2 K or 77 K, said areas having a working detector layer on a quantum well formed from a narrow-bandgap three-component solid solution of Hg1.xCdxTe and enclosed between barrier layers of a wide-bandgap three-component solid solution of Cd_yHg_1-yTe, where y is a value preferably in the range from 65% to 72%, and a means of maintaining said temperature, for areas of the multilayer semiconductor heterostructure with selected terahertz frequency subranges of the received radiation, given by the following intervals of energy values of the received radiation ħω: 8-16, 16-24, 24-32, 32-40, 40-48, 48-56, 56-64 meV, the width of the quantum well is equal to 11 nm with content of Cd in the working detector layer on the quantum well - Hg_1-xCd_xTe on series-distributed areas of the photodetector line in accordance with said terahertz frequency subranges of the received radiation at temperature of 4.2 K, defined by the following intervals of values x, respectively: 7.1-7.9, 7.9-8.7,8.7-9.4,9.4-10.1, 10.1-10.9, 10.9-11.5, 11.5-12.2%, or at temperature of 77 K, defined by the following intervals of values x, respectively: 5-5.9, 5.9-6.7, 6.7-7.5, 7.5-8.3, 8.3-9.0, 9.0-9.8, 9.8-10.5%.

EFFECT: invention improves manufacturability of desired terahertz photodetectors by creating structural conditions for operation of the photodetector element on the level of stable high sensitivity in different subranges in a wide frequency range of the terahertz received radiation depending on the width of the quantum well.

3 cl, 2 tbl, 2 dwg

Description

The group of inventions relates to nano-optoelectronics, in particular to photosensitive solid-state nanostructures, and in particular to a design and technological arsenal of microphysical materials science tools in the form of advanced quantum-dimensional structures based on a three-component CdHgTe solid solution that increase their efficiency in photoreceiving devices in quantum terahertz .

The current direction in the field of photosensitive solid-state semiconductor structures, represented by a three-component solid solution CdHgTe, is relevant due to the high sensitivity and resolution of photodetectors based on the specified photosensitive material in the wide infrared range of the received radiation (see A. Rogalski's article “HgCdTe infrared detector material: history , status and outlook "Rep. Prog. Phys. 68 (2005) 2267-2336).

At the same time, the practical problem situation in the field of creating new types of terahertz radiation detectors with a photodetector in the form of a photosensitive multilayer semiconductor heterostructure based on a three-component CdHgTe solid solution having a working detector layer with the properties of a quantum well is characterized by technological instability of the quality of the photodetector, expressed in instability (scatter) of sensitivity in various receiving cells of such photodetectors.

The well-known photosensitive structure is not without its drawback (see article C. Grein, N. Young, R. Singh and M. FIatte "Comparison of normal and inverted band structure HgTe / CdTe superlattices for very long wavelength infrared detectors" Journal of Electronic Materials , v. 43, No. 6, 2005, p.905-908), selected by the applicant as a prototype of the claimed photosensitive structure and which is a multilayer semiconductor heterostructure with a quantum well, sensitive to terahertz radiation at a temperature of the effective photocurrent, made in the form of a layer of a narrow-gap solid solution containing hg and te and enclosed between the barrier layers of the wide-gap ternary solid solution Cd _y Hg _1-y Te, where y is in the preferred range from 65% to 72%.

The objective of the claimed group of inventions is the development of technological capabilities of instrumentation in the field of terahertz photodetectors as a result of the development of an improved terahertz radiation sensitive multilayer semiconductor heterostructure with a quantum well, made in the form of a layer of narrow-gap solid solution Hg _1-x Cd _x Te and characterized by a stable distribution of high sensitivity element in the given terahertz subranges of the frequencies of the received radiation at temperatures e effective photocurrent depending on the width of the quantum well and the composition of the specified solid solution.

The technical result of the claimed group of inventions is to increase the manufacturability of manufacturing target terahertz photodetectors by creating constructive conditions for the functioning of the photodetector at a stable high sensitivity in different subbands in a wide frequency range of terahertz received radiation at a temperature of 4.2K or 77K depending on the width of the quantum well of the thickness working detector layer made of a three-component solid solution Hg _1-x Cd _x Te, and the content of Cd ( value x) in the range from 4% to 12%.

To achieve the specified technical result in a photosensitive structure, which is sensitive to terahertz radiation at a temperature of the effective photocurrent, a multilayer semiconductor heterostructure with a quantum well made in the form of a layer of a narrow-gap solid solution containing Hg and Te and enclosed between the barrier layers of a wide-gap three-component solid solution Cd _y Hg _1-y Te, where y is a value in the preferred range of 65% to 72%, the narrow-gap quantum well layer is formed of three component solid solution Hg _1-x Cd _x Te with a Cd content determined by x in the range from 4% to 12%, and the quantum well width is selected for a given terahertz frequency range of the received radiation at a temperature of 4.2 K or 77 K depending on the Cd content in accordance with table 1 below in the description of the invention.

To achieve the technical result in the case of the implementation of the inventive photosensitive structure in the form of a target terahertz photodetector device - a selective photodetector device, the latter containing a terahertz radiation sensitive photodetector, which is sequentially distributed and having effective photosensitivity in various terahertz subranges at a temperature of 4.2K or 77K sections of a multilayer semiconductor heterostructure with a working detector a quantum well layer formed from a narrow-gap three-component solid solution Hg _1-x Cd _x Te and enclosed between the barrier layers of a wide-gap three-component solid solution Cd _y Hg _1-y Te, where y is a value in the preferred range from 65% to 72%, and means for maintaining the indicated temperature, for sections of a multilayer semiconductor heterostructure with selected terahertz subbands of frequencies of received radiation, given by the following intervals of values of the energy of received radiation ħω: 8-16, 16-24, 24-3 2, 32-40, 40-48, 48-56, 56-64 meV, the width of the quantum well is 11 nm when the Cd content in the working detector layer on the quantum well is Hg _1-x Cd _x Te in successively distributed sections of the photodetector line in in accordance with the indicated terahertz frequency subbands of the received radiation at a temperature of 4.2 K, determined, respectively, by the following intervals of values of x: 7.1-7.9, 7.9-8.7, 8.7-9.4, 9.4-10.1, 10.1-10.9, 10.9-11.5, 11.5-12.2% , or at a temperature of 77 ° K, determined, respectively, by the following intervals of x: 5-5.9, 5.9-6.7, 6.7-7.5, 7.5-8.3, 8.3-9.0, 9.0-9.8, 9.8-10.5%.

In the particular case of the implementation of a selective photodetector, sections of a multilayer semiconductor heterostructure with a working detector layer on a quantum well are each made in the form of layers epitaxially sequentially formed on a GaAs (013) substrate: a buffer layer — ZnTe, a buffer layer — CdTe, two barrier quantum-dimensional layers — Cd _0.7 Hg _0.3 Te with the mentioned working detector layer located between them - Hg _1-x Cd _x Te and the coating layer - CdTe.

Figure 1 shows a diagram of the inventive photosensitive structure, figure 2 is a diagram of the inventive selective photodetector.

The proposed photosensitive structure in the exemplary embodiment (see Fig. 1) contains layers epitaxially sequentially formed on a GaAs (013) substrate 1: buffer layer 2 — ZnTe, buffer layer 3 — CdTe, lower barrier quantum layer 4 —, working detector layer 5 — Hg _1-x Cd _x Te, the upper quantum-barrier layer 6 - and the coating layer 7 - CdTe, the thickness of the working of the detection layer (the width of the quantum well) is selected for the desired subband terahertz radiation received frequency intervals given by taking the quantities of energy ħω direct radiation at a temperature effective photocurrent 4.2 K or 77 K, depending on the content of Cd in the detection layer operational -quantum well (value of x), indicated in Table 1.

The proposed photosensitive structure with a physical mechanism for the photosensitivity of the working detector layer of the 5-quantum well, similar to the process of excitation of interband transitions in known photodetectors (see, for example, the book S.Zi. Physics of semiconductor devices. - Moscow, Mir, 1984, vol. 2 , p.339-340), provides the ability to identify zones of optimal implementation of the target photodetector based on it. Moreover, the inventive photosensitive structure based on a working detector layer on a quantum well formed from a narrow-gap three-component solid solution Hg _1-x Cd _x Te, characterized by the parameters in table 1, expands the design capabilities of photodetector instrumentation as a result of the creation of an industrial and technological base for structural modeling of expected properties photodetector elements with a high degree of reliability.

So, for example, to create a photodetector with sensitivity in the frequency domain of the detected signal 3 THz (12 meV) using table 1 (see line: 8-16 meV), it is possible to set growth parameters (composition and width of the working layer - quantum well) in the manufacture of the specified device. Moreover, the width of the formed working layer may vary depending on technological conditions in the range from 8 to 11 nm. Thus, using the table below, a calibrated set of parameters is required for the fabricated photodetector structure, which is in demand in the technological development of the growth of high-quality structures.

To obtain a workable multilayer photosensitive heterostructure based on Hg _1-x Cd _x Te / Cd _y Hg _1-y Te with high quantum efficiency, it is necessary to use a working detector layer with a “non-inverted” band structure, i.e. in the case of the HgTe quantum well (photosensitive structure - prototype), the thickness of the edge of the edge of the edge should be less than 6.3 nm. However, the manufacturing technology of such layers has a growth error of ~ 0.5 nm, that is, 8%, which gives a sufficiently large scatter of parameters in the manufacture of structures. In addition, a small layer thickness increases scattering at the heterointerface and reduces carrier mobility, which reduces the photosensitivity of the structure.

To solve these problems, it is proposed in this application to form an epitaxial layer — a quantum well, not from pure HgTe, but from Hg _1-x Cd _x Te, that is, from a three-component solid solution with a certain fraction of Cd. Dosed addition of Cd to the working detector layer allows one to increase the thickness of the indicated layer (the width of the quantum well), while ensuring the same energy of the band gap (and, therefore, the same energy of the received terahertz radiation) as in the working detector layer of pure HgTe. The manufacture of a wider quantum well can reduce the effect of scattering at the heterointerface and increase the mobility of the carriers of the working layer, and, consequently, the sensitivity of the photodetector.

The stated possibilities are implemented in the proposed selective photodetector (see Fig. 2), which contains a terahertz radiation sensitive photodetector 8, which is sequentially distributed and having effective photosensitivity in different terahertz subranges at a temperature of 4.2 K or 77 K, sections of a multilayer semiconductor heterostructure with a working a quantum well detector layer formed from a narrow-gap three-component solid solution Hg _1-x Cd _x Te and enclosed between cryostat three-component solid solution Cd _y Hg _1-y Te, where y is a value in the preferred range from 65% to 72%, and the means for maintaining this temperature is a cryostat 9.

At the same time, for sections of the indicated multilayer semiconductor heterostructure with selected terahertz subranges of the frequencies of the received radiation, given by the following intervals of the received radiation energies аемогоω: 8-16, 16-24, 24-32, 32-40, 40-48, 48-56, 56 -64 meV, the width of the quantum well is 11 nm (optimal from the point of view of ensuring stable high sensitivity in parts of the photodetector line) when the Cd content in the working detector layer in the quantum well is Hg _1-x Cd _x Te in sequentially distributed sections of the photodetector line 8 in accordance with the indicated terahertz frequency subbands of the received radiation at a temperature of 4.2 K, determined, respectively, by the following intervals of values of x: 7.1-7.9, 7.9-8.7, 8.7-9.4, 9.4-10.1, 10.1-10.9, 10.9-11.5, 11.5 -12.2%, or at a temperature of 77 ° K, determined, respectively, by the following intervals of x: 5-5.9, 5.9-6.7, 6.7-7.5, 7.5-8.3, 8.3-9.0, 9.0-9.8, 9.8-10.5%.

A multichannel ohmmeter 10 is connected to a photodetector line 8 with the characterized sections of its multilayer semiconductor heterostructure (a line of photodetector elements in the form of a sequential set of photosensitive elements with a band gap that increases in accordance with the intervals of the received radiation energy ħω of the heterostructure sections) (for example, several Keithley devices 2400 combined in a common data bus) connected to a computer 11.

Selective photodetector allows you to determine the energy of the incident monochromatic radiation. Depending on the energy of the quanta of radiation incident on the device, in photosensitive areas - photodetector elements; made on the basis of the inventive multilayer semiconductor heterostructure, the band gap of which exceeds the energy of the incident radiation of the signal, the photocurrent will not occur, while on the photodetector elements whose band gap is less than the energy of the quanta of the incident radiation, the photocurrent signal will be observed. The energy of the quanta of the incident radiation will correspond to the energy of the band gap of the photodetector element from which there is a signal with the maximum band gap.

The basis for the development of the proposed group of inventions was the following calculation justification of table 1.

The calculation of the band structure of the quantum well was carried out in the framework of the four-band model and is based on the well-known method of envelope functions (see the article by M. G. Burt, J.Phys .: Condens. Matter 4, 6651 (1992)).

The wave function of the electron is presented in the form of expansion in the Bloch functions of the edges of the bands (k = 0):

. $$\Psi \left(r\right)=\exp \left(i{k}_{x}x+i{k}_{y}y\right){\displaystyle \sum _j{F}_j\left(z\right)u_j\left(r\right)}$$

.

The functions u _j (r) are chosen to be the same as in the well-known work (see the article by E.G. Novik, A. Pfeuffer-Jeschke, T. Jungwirth, V. Latussek, C.R. Becker, G. Landwehr, H. Buhmann , and LW Molenkamp, Phys. Rev. B 72, 35321 (2005)) and are considered the same for all semiconductors forming a heterostructure in accordance with the above method (see the article by M. G. Burt).

The envelope functions F _j (z) are sought as solutions of the stationary Schrödinger equation with the 8 × 8 Hamiltonian taking into account the built-in deformation:

$$\left(\begin{array}{ccc}{H}_{\mathrm{eleven}}\left(k_x,k_y,{\widehat{k}}_z\right)& ...& H_{\mathrm{eighteen}}\left(k_x,k_y,{\widehat{k}}_z\right)\\ ⋮& \ddots & ⋮\\ H_{81}\left(k_x,k_y,{\widehat{k}}_z\right)& ...& H_{88}\left(k_x,k_y,{\widehat{k}}_z\right)\end{array}\right)\left(\begin{array}{c}{F}_{\mathrm{one}}\left(z\right)\\ ⋮\\ F_8\left(z\right)\end{array}\right)=E\left(k_x,k_y\right)\left(\begin{array}{c}{F}_{\mathrm{one}}\left(z\right)\\ ⋮\\ F_8\left(z\right)\end{array}\right)$$

In the calculations, the following Hamiltonian was used:

Where

k _± = k _x ± ik _y

$$k_z=-i\frac{\partial }{{\partial }_z}$$

$$T=E_v+E_g+\frac{{\mathrm{<figure-callout\; id="2"\; label="ħ"\; filenames="00000021.png"\; state="\{\{state\}\}">\hslash </figure-callout>}}^2}{2m_0}\left[\left(2F+\mathrm{one}\right)\left(k_x^2+k_y^2\right)+k_z\left(2F+\mathrm{one}\right)k_z\right]+{\text{a}}_c\left(2{\epsilon }_{xx}+{\epsilon }_{zz}\right),$$

$$U=E_v-\frac{{\mathrm{<figure-callout\; id="2"\; label="ħ"\; filenames="00000021.png"\; state="\{\{state\}\}">\hslash </figure-callout>}}^2}{2m_0}\left[{\gamma }_{\mathrm{one}}\left(k_x^2+k_y^2\right)+k_z{\gamma }_{\mathrm{one}}{k}_z\right]+{\text{a}}_v\left(2{\epsilon }_{xx}+{\epsilon }_{zz}\right),$$

$$\begin{array}{l}V=-\frac{{\mathrm{<figure-callout\; id="2"\; label="ħ"\; filenames="00000021.png"\; state="\{\{state\}\}">\hslash </figure-callout>}}^2}{2m_0}\left[{\gamma }_2{k}_x^2+\left(\frac{23}{\mathrm{fifty}}{\mathrm{<figure-callout\; id="2"\; label="\gamma "\; filenames="00000021.png"\; state="\{\{state\}\}">\gamma </figure-callout>}}_2+\frac{27}{\mathrm{fifty}}{\gamma }_3\right)k_y^2-\frac{\mathrm{eighteen}}{25}{k}_y\left\{{\gamma }_2-{\mathrm{<figure-callout\; id="3"\; label="\gamma "\; filenames="00000021.png"\; state="\{\{state\}\}">\gamma </figure-callout>}}_3,k_z\right\}-k_z\left(\frac{73}{\mathrm{fifty}}{\mathrm{<figure-callout\; id="2"\; label="\gamma "\; filenames="00000021.png"\; state="\{\{state\}\}">\gamma </figure-callout>}}_2+\frac{27}{\mathrm{fifty}}{\gamma }_3\right)k_z\right]+\\ +\left(\frac{73}{\mathrm{one\; hundred}}b+\frac{9\sqrt{3}}{\mathrm{one\; hundred}}d\right)\left({\epsilon }_{xx}-{\epsilon }_{zz}\right)+\left(\frac{\mathrm{eighteen}}{25}b-\frac{6\sqrt{3}}{25}d\right){\epsilon }_{yz}\end{array}$$

$$\begin{array}{l}R=-\frac{{\mathrm{<figure-callout\; id="2"\; label="ħ"\; filenames="00000021.png"\; state="\{\{state\}\}">\hslash </figure-callout>}}^2}{2m_0}\sqrt{3}[-{\gamma }_2{k}_x^2+2i{\gamma }_3{k}_x{k}_y+{\gamma }_2{k}_x^2+\left(\frac{41}{\mathrm{fifty}}{\mathrm{<figure-callout\; id="2"\; label="\gamma "\; filenames="00000021.png"\; state="\{\{state\}\}">\gamma </figure-callout>}}_2+\frac{9}{\mathrm{fifty}}{\gamma }_3\right){\mathrm{<figure-callout\; id="2"\; label="k\; y"\; filenames="00000021.png"\; state="\{\{state\}\}">k\; </figure-callout>}}_y^{}+\\ \end{array}$$

$$+\frac{6}{25}{k}_y\left\{\left({\gamma }_2-{\gamma }_3\right),k_z\right\}+\frac{9}{\mathrm{fifty}}{k}_z\left({\gamma }_2-{\gamma }_3\right)k_z]+$$

$$+\left(\frac{9}{\mathrm{one\; hundred}}d-\frac{9\sqrt{3}}{\mathrm{one\; hundred}}b\right)\left({\epsilon }_{xx}-{\epsilon }_{zz}\right)+\left(\frac{6\sqrt{3}}{25}b-\frac{6}{25}d\right){\epsilon }_{yz}$$

$${\overline{S}}_{\pm }=-\frac{{\mathrm{<figure-callout\; id="2"\; label="ħ"\; filenames="00000021.png"\; state="\{\{state\}\}">\hslash </figure-callout>}}^2}{2m_0}\sqrt{3}[k_x\left\{{\mathrm{<figure-callout\; id="3"\; label="\gamma "\; filenames="00000021.png"\; state="\{\{state\}\}">\gamma </figure-callout>}}_3,k_z\right\}+k_x\left\{\kappa ,k_z\right\}\pm \frac{12i}{25}\left({\gamma }_2-{\gamma }_3\right){\mathrm{<figure-callout\; id="2"\; label="k\; y"\; filenames="00000021.png"\; state="\{\{state\}\}">k\; </figure-callout>}}_y^{}\pm \frac{i}{25}{k}_y\left\{\left(16{\mathrm{<figure-callout\; id="3"\; label="\gamma "\; filenames="00000021.png"\; state="\{\{state\}\}">\gamma </figure-callout>}}_3+9{\gamma }_2\right),k_z\right\}\pm$$

$$\pm i{k}_y\left\{\kappa ,k_z\right\}\mp \frac{12i}{25}{k}_z\left({\gamma }_2-{\gamma }_3\right)k_z]\pm \frac{6i}{25}\left(\sqrt{3}b-d\right)\left({\epsilon }_{xx}-{\epsilon }_{zz}\right)\pm \frac{i}{25}\left(9\sqrt{3}b+16d\right){\epsilon }_{yz}$$

$${\overline{S}}_{\pm }=-\frac{{\mathrm{<figure-callout\; id="2"\; label="ħ"\; filenames="00000021.png"\; state="\{\{state\}\}">\hslash </figure-callout>}}^2}{2m_0}\sqrt{3}[k_x\left\{{\mathrm{<figure-callout\; id="3"\; label="\gamma "\; filenames="00000021.png"\; state="\{\{state\}\}">\gamma </figure-callout>}}_3,k_z\right\}-\frac{\mathrm{one}}{3}{k}_x\left\{\kappa ,k_z\right\}\pm \frac{12i}{25}\left({\gamma }_2-{\gamma }_3\right){\mathrm{<figure-callout\; id="2"\; label="k\; y"\; filenames="00000021.png"\; state="\{\{state\}\}">k\; </figure-callout>}}_y^{}\pm \frac{i}{25}{k}_y\left\{\left(16{\mathrm{<figure-callout\; id="3"\; label="\gamma "\; filenames="00000021.png"\; state="\{\{state\}\}">\gamma </figure-callout>}}_3+9{\gamma }_2\right),k_z\right\}\mp$$

$$\mp \frac{\mathrm{one}}{3}i{k}_y\left\{\kappa ,k_z\right\}\mp \frac{12i}{25}{k}_z\left({\gamma }_2-{\gamma }_3\right)k_z]\pm \frac{6i}{25}\left(\sqrt{3}b-d\right)\left({\epsilon }_{xx}-{\epsilon }_{zz}\right)\pm \frac{i}{25}\left(9\sqrt{3}b+16d\right){\epsilon }_{yz}$$

. $$C=\frac{{\hslash }^2}{m_0}{k}_{-}\left[\kappa ,{\widehat{k}}_z\right]$$

.

The symbol "+" as a superscript means Hermitian conjugation.

The expression for the Hamiltonian of the heterostructure grown on the (013) plane was obtained by the method described in the work (see the article by J. Los, A. Fasolino, A. Catellani, Phys. Rev. B 53, 4630 (1996)). The components of the built-in strain tensor for a layer with a lattice constant and in the case of direction (013) are calculated by the following formulas:

, ε_xz=0, $${\epsilon }_{xx}={\epsilon }_{yy}=\frac{{\text{a}}_0-\text{a}}{\text{a}}$$

, ε _xz = 0,

, $${\epsilon }_{yz}=\frac{12\left(C_{\mathrm{eleven}}+2C_{12}\right)\left(C_{12}-C_{\mathrm{eleven}}+2C_{44}\right)}{9C_{\mathrm{eleven}}^2-9C_{12}^2+C_{44}\left(82C_{\mathrm{eleven}}-\mathrm{eighteen}{C}_{12}\right)}{\epsilon }_{xx}$$

,

, $${\epsilon }_{zz}=-\frac{9C_{\mathrm{eleven}}^2+\mathrm{eighteen}{C}_{\mathrm{eleven}}\left(C_{12}-C_{44}\right)-27C_{12}^2+146C_{44}{C}_{12}}{9C_{\mathrm{eleven}}^2-9C_{12}^2+C_{44}\left(82C_{\mathrm{eleven}}-\mathrm{eighteen}{C}_{12}\right)}{\epsilon }_{xx}$$

,

where a ₀ is the lattice constant of the buffer layer, and the x, y, and z coordinate axes are directed along (100), (0 3-1) and (013), respectively. In the calculations, the band parameters of the materials from the above work (see the article by E.G. Novik et al.) And the values of the elastic moduli C _ij from the work (see the article by K. Takita, K. Onabe, S. Tanaka, Phys. Stat. Sol. (B) 92, 297 (1997)). In this case, the dependences on the concentration of the solid solution are considered linear for all quantities except the band gap. The formula from the work is used for it (see the article by C.R. Becker, V. Latussek, A. Pfeuffer-Jeschke, G. Landwehr, and LW Molenkamp, Phys. Rev. B 62, 10353 (2000)).

The values of these parameters are given in table 2.

table 2 Cdte Hgte Hg _1-x Cd _x Te E _g , meV 1606 -303 1606х-303 (1-х) -132х (1-х) a, Å 6.48 6.46 A _CdTe x + A _HgTe (1-x) E _v , meV -570 0 Δ, meV 910 1080 F -0.09 0 P, meV · Å 96.95 96.95 γ ₁ 1.47 4.1 γ ₂ -0.28 0.5 γ ₃ 0.03 1.3 κ -1.31 -0.4 a _c , meV -2925 -2380 a _v , meV 0 1310 b, meV -1200 -1500 d, meV -5400 -2500 C ₁₁ , 10 ¹¹ dyne / cm ² 5.62 5.92 C ₁₂ , 10 ¹¹ dyne / cm ² 3.94 4.14 C ₄₄ , 10 ¹¹ dyne / cm ² 2.06 2.19

To calculate the envelopes of functions and the corresponding electron energy values, the structure is presented in the form of a superlattice of weakly coupled quantum wells. The lattice period L is chosen so that the interaction of the wells does not have a noticeable effect on the energy spectrum. The calculations were carried out by the method of expansion of the envelopes of the wave function in plane waves:

, $$F_j\left(z\right)={\displaystyle \sum _{n=-N}^N{f}_j\left(n\right)\frac{\mathrm{one}}{\sqrt{L}}\exp \left(\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="00000021.png"\; state="\{\{state\}\}">i</figure-callout>}\frac{2\pi n}{L}z\right)}$$

,

where N determines the maximum wave number used in the expansion (the total number of basis elements is 2N + 1).

Claims (3)

1. A photosensitive structure, which is a terahertz radiation sensitive at an effective photocurrent temperature, multilayer quantum well semiconductor heterostructure made in the form of a layer of a narrow-gap solid solution containing Hg and Te and enclosed between the barrier layers of a wide-gap three-component solid solution Cd _y Hg _1-y Te where y is a value in the preferred range from 65% to 72%, characterized in that the narrow-gap layer of the quantum well is formed from a three-component solid ora Hg _1-x Cd _x Te with a content of Cd, determines the value x in the range from 4% to 12%, the width of the quantum well is chosen for a given subband of the received terahertz radiation at frequencies of 4.2 ° K and 77 ° K depending upon the the content of Cd in accordance with table 1 in the description of the invention. 2. A selective photodetector containing a terahertz radiation sensitive photodetector, which is sequentially distributed and having effective photosensitivity in different terahertz subbands at a temperature of 4.2 ° K or 77 ° K, sections of a multilayer semiconductor heterostructure with a working quantum well formed detector layer from a narrow-gap three-component solid solution Hg _1-x Cd _x Te and enclosed between the barrier layers of a wide-gap three-component solid Cd _y Hg _1-y Te solution, where y is a value in the preferred range from 65% to 72%, and a means of maintaining the indicated temperature, characterized in that for sections of a multilayer semiconductor heterostructure with selected terahertz frequency subbands of the received radiation, given by the following ranges of values received radiation energy ħω: 8-16, 16-24, 24-32, 32-40, 40-48, 48-56, 56-64 meV, the width of the quantum well is 11 nm with a Cd content in the working detector layer on the quantum well - Hg _1-x Cd _x Te on sequentially distributed sections of the photodetector line in accordance with the indicated terahertz frequency subbands of the received radiation at a temperature of 4.2 K, determined, respectively, by the following intervals of values of x: 7.1-7.9, 7.9-8.7, 8.7-9.4, 9.4-10.1, 10.1-10.9, 10.9-11.5 , 11.5-12.2%, or at a temperature of 77 K, determined respectively by the following intervals of x: 5-5.9, 5.9-6.7, 6.7-7.5, 7.5-8.3, 8.3-9.0, 9.0-9.8, 9.8-10.5%. 3. The selective photodetector according to claim 2, characterized in that the sections of a multilayer semiconductor heterostructure with a working detector layer on a quantum well are each made in the form of layers epitaxially sequentially formed on a GaAs (013) substrate: buffer layer — ZnTe, buffer layer — CdTe, two barrier quantum-well layers - Cd_0.7Hg_0.3Te with the mentioned working detector layer located between them - Hg_1-xCd_xTe and topcoat - CdTe.

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