Semiconductor quantum dot structure

Abstract

The utility model relates to the technical field of InAs / GaSb infrared detectors, and particularly discloses a semiconductor quantum dot structure, which comprises a GaAs buffer layer, an InAs layer, a GaSb layer and a GaAs cover layer, the InAs layer is arranged on one surface of the GaAs buffer layer, the GaSb layer is arranged on one surface of the InAs layer far away from the GaAs buffer layer, the GaAs cover layer is arranged on one surface of the GaSb layer far away from the InAs layer, and the quantum dot density is reduced along with the increase of the GaSb deposition amount. When the GaSb deposition amount reaches 3.0 monatomic layers, the wavelength of the light-emitting peak exceeds 1.55 microns, and it is found that the red shift of the light-emitting peak is caused by the change of an electron-hole composite transition light-emitting mechanism in the quantum dots; namely, I-type transition luminescence between electrons and holes limited in the InAs layer is converted into II-type transition luminescence between the electrons in the InAs layer and the holes in the GaSb layer.

Description

Technical Field

[0001] The utility model relates to the technical field of InAs / GaSb infrared detectors, in particular to a semiconductor quantum dot structure. Background Art

[0002] Quantum dot lasers have become a hot topic of international research due to their excellent properties such as high temperature stability, high modulation rate and narrow linewidth. The In(Ga)As / GaAs self-organized quantum dot system has been widely studied because of its wide energy band adjustment range and its luminescence can cover the two important communication bands of 1.3μm and 1.55μm.

[0003] At present, great progress has been made in high-performance 1.3μm InAs / GaAs quantum dot lasers, but it is still difficult to obtain high-quality 1.55μm InAs / GaAs quantum dot materials. In order to obtain longer wavelength InAs / GaAs quantum dot luminescence, some scholars have proposed the use of GaSb / InAs / GaAs heterojunction quantum dots, that is, after growing InAs quantum dots, a certain amount of GaSb is deposited. Since the crystal structure and lattice constant of GaSb and InAs are similar, the later deposited GaSb is more likely to cover the InAs dots rather than forming another GaSb dot.

[0004] However, in the above-mentioned prior art, it is difficult to obtain high-quality 1.55 μm luminescent quantum dot materials. Utility Model Content

[0005] The utility model aims to provide a semiconductor quantum dot structure, aiming to solve the technical problem in the prior art that it is difficult to obtain high-quality 1.55μm luminescent quantum dot materials.

[0006] To achieve the above-mentioned purpose, the utility model adopts a semiconductor quantum dot structure, including a GaAs buffer layer, an InAs layer, a GaSb layer and a GaAs cap layer, wherein the InAs layer is arranged on one side of the GaAs buffer layer, the GaSb layer is arranged on one side of the InAs layer away from the GaAs buffer layer, and the GaAs cap layer is arranged on one side of the GaSb layer away from the InAs layer.

[0007] Wherein, the deposition amount of the GaAs buffer layer is 150nm.

[0008] Wherein, the deposition amount of the GaAs cap layer is 100nm.

[0009] Wherein, the deposition amount of the InAs layer is 2.4ML.

[0010] Wherein, the growth rate of the InAs layer is 0.09 ML / s.

[0011] Wherein, the growth rate of the GaSb layer is 0.3 ML / s.

[0012] The utility model discloses a semiconductor quantum dot structure. All samples are grown in a VG80HMKII molecular beam epitaxy system. The rotation speed of the GaAs substrate is 20 rpm. The heating and cooling speeds of the GaAs substrate are both 30°C / min. After the GaAs substrate is deoxidized, a 150nm deposited GaAs buffer layer is first grown at a temperature of 580°C, and then the temperature is lowered to 500°C to grow quantum dots. When about 2.1ML of the InAs layer is grown on the GaAs buffer layer, points on a RHEED graph are in a V shape with an angle of about 43°. When the GaSb layer is deposited on the InAs layer, the V-shaped "tail" gradually weakens until it disappears, indicating that the deposition of the GaSb layer changes the shape of the quantum dots of the InAs layer. When the GaAs cap layer is initially grown, the V-shaped shape reappears and disappears as the growth thickness of the GaAs cap layer increases. As the amount of GaSb layer deposited increases, the density of quantum dots gradually decreases. When the amount of GaSb layer deposited increases to 3.0 ML, the density of quantum dots drops to 2×10 10 / cm 2 Therefore, increasing the deposition amount of the GaSb layer is approximately equivalent to increasing the deposition amount of quantum dots in the InAs layer, resulting in point merging and density reduction. When 3.0ML of the GaSb layer is deposited on the InAs layer, the quantum dot size distribution is still relatively uniform. This method can effectively solve the problem in the prior art that it is difficult to obtain high-quality 1.55μm luminescent quantum dot materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0014] Figure 1 It is a schematic diagram of the InAs / GaSb heterojunction quantum dot structure of the utility model.

[0015] Figure 2 This is a PL diagram of quantum dots with different GaSb layer deposition amounts of the present invention.

[0016] Figure 3 This is the PL spectrum of quantum dots under 1.2MLGaSb of the utility model.

[0017] Figure 4This is the PL spectrum of quantum dots under 3.0MLGaSb of the utility model.

[0018] Figure 5 This is a schematic diagram of the quantum dot energy band structure of the utility model with a 1.2MLGaSb layer deposition amount.

[0019] Figure 6 It is a schematic diagram of the quantum dot energy band structure of 3.0MLGaSb layer deposition amount of the utility model.

[0020] Figure 7 It is the quantum dot PL spectrum of the sample with 3.0MLGaSb layer deposition amount at different temperatures of the utility model.

[0021] 101 - GaAs buffer layer, 102 - InAs layer, 103 - GaSb layer, 104 - GaAs cap layer. DETAILED DESCRIPTION

[0022] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0023] See also Figure 1 to Figure 7 ,in Figure 1 This is a schematic diagram of the InAs / GaSb heterojunction quantum dot structure of the utility model. Figure 2 This is the PL diagram of quantum dots with different GaSb layer deposition amounts of the utility model. Figure 3 This is the PL spectrum of quantum dots under 1.2MLGaSb of the utility model. Figure 4 This is the quantum dot PL spectrum of the utility model under 3.0MLGaSb, Figure 5 This is a schematic diagram of the quantum dot energy band structure of the utility model with a 1.2MLGaSb layer deposition amount. Figure 6 This is a schematic diagram of the quantum dot energy band structure of the utility model with a 3.0MLGaSb layer deposition amount. Figure 7 It is the quantum dot PL spectrum of the sample with 3.0MLGaSb layer deposition amount at different temperatures of the utility model.

[0024] The utility model provides a semiconductor quantum dot structure, comprising a GaAs buffer layer 101, an InAs layer 102, a GaSb layer 103 and a GaAs cap layer 104, wherein the InAs layer 102 is arranged on one side of the GaAs buffer layer 101, the GaSb layer 103 is arranged on one side of the InAs layer 102 away from the GaAs buffer layer 101, the GaAs cap layer 104 is arranged on one side of the GaSb layer 103 away from the InAs layer 102, the deposition amount of the GaAs buffer layer 101 is 150nm, the deposition amount of the GaAs cap layer 104 is 100nm, the deposition amount of the InAs layer 102 is 2.4ML, the growth rate of the InAs layer 102 is 0.09ML / s, and the growth rate of the GaSb layer 103 is 0.3ML / s.

[0025] In this embodiment, all samples are grown in a VG80HMKII molecular beam epitaxy system, the rotation speed of the GaAs substrate is 20 rpm, the heating and cooling rates of the GaAs substrate are both 30°C / min, and after deoxidation of the GaAs substrate, a 150 nm deposited GaAs buffer layer 101 is first grown at 580°C, and then the temperature is lowered to 500°C to grow quantum dots. When about 2.1 ML of the InAs layer 102 is grown on the GaAs buffer layer 101, the points on the RHEED graph are in a V shape with an angle of about 43°. When the GaSb layer 103 is deposited on the InAs layer 102, the V-shaped "tail" gradually weakens until it disappears, indicating that the deposition of the GaSb layer 103 changes the shape of the quantum dots of the InAs layer 102. When the GaAs cap layer 104 initially grows, the V-shaped shape reappears and disappears as the thickness of the GaAs cap layer 104 increases. As the deposition amount of the GaSb layer 103 increases, the density of quantum dots gradually decreases. When the deposition amount of the GaSb layer 103 increases to 3.0 ML, the density of quantum dots decreases to 2×10 10 / cm 2 Therefore, increasing the deposition amount of the GaSb layer 103 is approximately equivalent to increasing the deposition amount of quantum dots in the InAs layer 102, resulting in point merging and density reduction. When 3.0ML of the GaSb layer 103 is deposited on the InAs layer 102, the quantum dot size distribution is still relatively uniform.

[0026] The beneficial effects of the utility model are as follows: all samples are grown in a VG80HMKII molecular beam epitaxy system, the rotation speed of the GaAs substrate is 20 rpm, the heating and cooling speeds of the GaAs substrate are both 30°C / min, the GaAs buffer layer 101 with a thickness of 150 nm is first grown at a temperature of 580°C after deoxidation of the GaAs substrate, and then the temperature is lowered to 500°C to grow quantum dots, when the InAs layer 102 with a thickness of about 2.1 ML is grown on the GaAs buffer layer 101, the points on the RHEED graph are in a V shape with an angle of about 43°, when the GaSb layer 103 is deposited on the InAs layer 102, the V-shaped "tail" gradually weakens until it disappears, indicating that the deposition of the GaSb layer 103 changes the shape of the quantum dots of the InAs layer 102, and when the GaAs cap layer 104 initially grows, the V-shaped shape reappears and disappears as the growth thickness of the GaAs cap layer 104 increases. As the deposition amount of the GaSb layer 103 increases, the density of quantum dots gradually decreases. When the deposition amount of the GaSb layer 103 increases to 3.0 ML, the density of quantum dots decreases to 2×10 10 / cm 2 Therefore, increasing the deposition amount of the GaSb layer 103 is approximately equivalent to increasing the deposition amount of quantum dots in the InAs layer 102, resulting in point merging and density reduction. After 3.0ML of the GaSb layer 103 is deposited on the InAs layer 102, the quantum dot size distribution is still relatively uniform. This method can effectively solve the problem in the prior art that it is difficult to obtain high-quality 1.55μm luminescent quantum dot materials.

[0027] The above disclosure is only a preferred embodiment of the present invention, and certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope covered by the utility model.

Claims

1. A semiconductor quantum dot structure, characterized in that: The invention comprises a GaAs buffer layer, an InAs layer, a GaSb layer and a GaAs cap layer, wherein the InAs layer is arranged on one side of the GaAs buffer layer, the GaSb layer is arranged on one side of the InAs layer away from the GaAs buffer layer, and the GaAs cap layer is arranged on one side of the GaSb layer away from the InAs layer.

2. The semiconductor quantum dot structure according to claim 1, characterized in that: The deposition amount of the GaAs buffer layer is 150nm.

3. The semiconductor quantum dot structure according to claim 2, characterized in that: The deposition amount of the GaAs cap layer is 100 nm.

4. The semiconductor quantum dot structure according to claim 3, characterized in that: The deposition amount of the InAs layer is 2.4 ML.

5. The semiconductor quantum dot structure according to claim 4, characterized in that: The growth rate of the InAs layer is 0.09 ML / s.

6. The semiconductor quantum dot structure according to claim 5, characterized in that: The growth rate of the GaSb layer is 0.3 ML / s.

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