The results of investigations by the method of Electron beam-induced current of p-n-junctions based on InP with GaP crystallites in the space charge region are presented. It is shown that the introduction of crystallites into the space charge region leads to short-circuiting of the p-n-junction. The quality of the material grown on top of the crystallites allows to create of photoactive regions, as evidenced by measurements of the photoluminescence spectra. Keywords: crystallites, tunnel junction, connecting element.

The technology for production one and two-cascade power laser converters was presented in this paper. According to the measurement results of the grown samples, an efficiency of 34.5

The results of investigations by the method of Electron beam-induced current of p-n junctions based on InP with GaP crystallites in the space charge region are presented. It is shown that the introduction of crystallites into the space charge region leads to short-circuiting of the p-n junction. The quality of the material grown on top of the crystallites allows to create of photoactive regions, as evidenced by measurements of the photoluminescence spectra.

В настоящее время, наиболее эффективные фотоэлементы изготавливаются на основе каскадных гетероструктур. В таких приборах фотоактивные p−n-переходы, работающие в разных спектральных диапазонах, соединяются последовательно туннельными переходами с предельно высокими уровнями легирования [1,2]. При достаточно высокой плотности излучения, генерируемый фототок может превысить пиковый ток туннельных переходов, что ведет к увеличению сопротивления всей структуры и падению эффективности работы прибора [3].

Results are reported of using subcontact layers with energy gap width E g of 0.35 to 0.8 eV for obtaining low-resistivity electrical contacts to p -InP. An experimental dependence of the contact resistance on E g of the subcontact material In x Ga 1 – x As was obtained.

The paper presents the results of using sub-contact layers with a band gap from 0.35 to 0.8 eV to obtain low-resistance electrical contacts to p-InP. An experimental dependence of the contact resistance on the band gap of the sub-contact material In(x)Ga(1-x)As is obtained.

In the study of doped anisotypic heterostructures with layers of Ga(1-x)In(x)P(1-y)As(y) grown on InP substrates with a buffer layer of InP by MOC-hydride epitaxy, the presence of transition regions was detected in the Ga(1-x)In(x)P(1-y)As(y) layer on the substrate side for individual samples, across which the arsenic content (y) increased from the interface with the InP layer to the surface of the structure by the amount of (Δy) up to 0.15, and the content of elements of the third group (x) remained constant.

When studying doped anisotypic heterostructures with Ga1 – xInxAsyP1 – y layers grown on InP substrates with an InP buffer layer by metal organic chemical vapor deposition, the presence of transition regions is revealed in the Ga1 – xInxAsyP1 – y layer from the side of the substrate in some of the samples, along which the arsenic content (y) increases from the interface with the InP layer to the surface of the structure by a Δy value of up to 0.15, while the content of elements of the third group (x) remains constant.

In this work, we studied the surface quality dependence of GaSb and InP substrates prepared by various methods of pre-epitaxial preparation, specifically, etching, annealing, and growing a buffer layer. Our main goal was to obtain the most efficient method of pre-epitaxial treatment, which allows preparing substrates with the best surface quality. The experimental results were evaluated by the parameter of the average roughness of the substrate. As a result a combination of the methods of pre-epithelial preparation of GaSb and InP substrates was selected, which made it possible to obtain a root-mean-square surface roughness about 0.6–0.8nm.

Abstract It is necessary to minimize the resistance of electrical contacts to reduce heat losses in photovoltaic converters of laser radiation. The paper describes ways to reduce the resistance of electrical contacts for p-InP by choosing the composition of the subcontact layer based on p-InGaAs. For this purpose, layers of p-InGaAs with different compositions and bandgaps were grown by the MOCVD method. AgMn/Ni/Au contact metallization was deposited on samples to compare the characteristics of electrical contacts. The minimum specific contact resistance was 7• 10−5 Ω-cm2 for the layer with Eg = 0.51 eV.

Luminescence properties of epilayers of Ga 1 – x In x As y P 1 – y (GaInAsP) solid solutions with graded content of Group V elements (Δ y up to 0.08 over a total thickness of about 1 μm) were studied at 77 and 300 K. The photoluminescence (PL) spectra of GaInAsP epilayers with large Δ y values were broadened. The GaInAsP epilayers of low crystalline perfection exhibited either no PL emission or showed PL spectra characteristic of transitions involving impurity energy levels.

The photoluminescent properties at 77 and 300 K are investigated for Ga1 xInxAsyP1 y epilayers with V-group elements content gradient Δy up to 0.08 across whole thickness (about 1 µm). Ga1 xInxAsyP1 y layers with high Δy values have widened photoluminescence spectra. For GaInAsP layers of low crystaline perfection, photoluminescence was either absent or manifested itself as it is typical for transitions involving impurity levels.

GaInPAs/InP heterostructures grown by low pressure (0.1 bar, 600 oC) metal-organic chemical vapor phase deposition were investigated. The thicknesses of grown GaInAsP layers were about 1 µm. For the epitaxial layers Ga1-xInxP1-yAsy) with average compositions of x = 0.77 – 0.87 and y = 0.07 – 0.42 the variation of V group elements content y with the epilayer depth were revealed, weher the compositions of V-group elements were changed up to Δy = 0.1 atomic fractions in V group elements sublattice. In most cases, y change occurs in a GaInAsP region up to 200 nm thick adjacent to the InP. In some cases, y changes throughout the whole GaInPAs layer thickness. Fo the epitaxial layers with a satisfactory crystal perfection the less was the mismatch between the substrate and the GaInPAs epitaxial layer, the smaller was the value of Δy. For GaInPAs layers characterized by a low degree of crystal perfection and a high lattice mismatch between GaInAsP and InP layers, the value of Δy was about zero. These data let us suggest that the incorporation of atoms of the V group in the epitaxial layer strongly depends on elastic deformation of the growing monolayer, that is mismatched with the underlying crystal surface.

GaInPAs/InP heterostructures grown by metalorganic chemical vapor-phase deposition at a temperature of 600°C and pressure of 0.1 bar are investigated. The thicknesses of the grown GaInAsP layers amount to about 1 μm. For Ga1 –xInxP1 –yAsy solid solutions with average compositions of x = 0.77–0.87 and y = 0.07–0.42, the variation in the content y of V-group atoms over the epitaxial-layer thickness by a value of Δy up to 0.1 atomic fractions in the sublattice of the V-group elements is revealed by secondary ion mass spectrometry. In most cases, a change in y occurs in the GaInAsP layer over a length to 200 nm from the InP heterointerface. In certain cases, y varies throughout the entire GaInPAs-layer thickness. For the epitaxial layers with satisfactory crystalline perfection, the value of Δy is less in the case of better lattice-matching between the GaInPAs epitaxial layer and the substrate. For GaInPAs layers strongly lattice-mismatched with the substrate and characterized by a low degree of crystalline perfection, the value of Δy is close to zero. All these facts enable us to assume that it is elastic deformations arising in the forming monolayer lattice-mismatched with the growing surface that affect the incorporation of V-group atoms into the forming crystalline lattice.

One of the interesting materials for the antireflective coatings of photovoltaic converters based on InP is the anodic oxide of indium phosphide. This material might be used as a first layer of a multilayer antireflection coating, as well as an independent single-layer antireflection coating. This paper deals with the study of the coating and research of its effect on the reflection coefficient from the InP surface.

In this paper, we report on the initial studies of connecting elements for cascade photodetectors. The heterostructures used in this work are based on InP. As a connecting element, it is proposed to use nanocrystalline inclusions instead of the tunnel junction. GaP nanocrystals are most suitable for this purpose because this material does not cause absorption of the incident radiation.

Some results of studies on the creation of new junction elements for application in monolithic multijunction InP based photovoltaic cells are presented. A new type of junction elements with a specific ohmic resistance of less than 2 mΩ cm2 within a range of current densities of up to 700 A/cm2 is presented as an alternative to tunnel junctions.

In this paper, we report on the initial studies of cascade photodetectors. The heterostructures used in this work are based on InP. InP is the most suitable material for converting the solar spectrum in the range from 0.95 to 1.2 μm. It is proposed to use nanocrystalline inclusions as a connecting element. For this, nanocrystals GaP are best suitable. Because this material (GaP) does not create an absorption of the incident radiation.

AbstractSome results of studies on the creation of new junction elements for application in monolithic multijunction InP based photovoltaic cells are presented. A new type of junction elements with a specific ohmic resistance of less than 2 mΩ cm^2 within a range of current densities of up to 700 A/cm^2 is presented as an alternative to tunnel junctions.

Photovoltaic laser-power converters with irradiation of the substrate side are developed based on lattice-matched GaInAs/InP heterostructures formed by metal-organic vapor-phase epitaxy. Variants of antireflection coatings with a reflection minimum at a wavelength of λ = 1064 nm as well as features of chip bonding using soldering pastes with different melting points are considered. The efficiency of 34.5% (1.2 W, λ =1064 nm) is achieved for the converters with the area of 3.5 × 3.5 mm2 at uniform radiation conditions.