Method for regulating wavelength of indium arsenide quantum dot by using arsenic pressure

Abstract

The present application relates to a kind of methods for regulating the wavelength of indium arsenide quantum dots by arsenic pressure, the method utilizes the rule that the wavelength of indium arsenide quantum dots changes with the change of arsenic pressure, and the required arsenic pressure of the indium arsenide quantum dots sample with the target luminescence wavelength is obtained by analyzing the measured arsenic pressure-peak luminescence wavelength curve.The present application has important significance for regulating the luminescence wavelength of quantum dots in practical application.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of semiconductor materials, and particularly relates to a method for regulating the wavelength of indium arsenide quantum dot luminescence by using arsenic pressure. BACKGROUND

[0002] With the increasing global data throughput, contemporary communication systems need faster transmission speed, wider bandwidth and lower power consumption. Traditional integrated circuit technology is subject to the physical limit of copper interconnection and cannot meet this demand, and optical interconnection becomes a new solution to solve the current inter-chip interconnection speed bottleneck. By combining silicon microelectronic circuits and light sources on the same chip, not only can high-speed, wide-band and low-power data transmission be achieved, but also large-scale and low-cost production can be achieved, which can improve economic efficiency while ensuring performance.

[0003] At present, the problem limiting the large-scale application of silicon photonics chips is that silicon cannot be made into a high-efficiency light source. Silicon and germanium are difficult to make high-quality light sources due to their own indirect bandgap properties, while III-V materials are ideal materials for preparing high-quality light sources due to their direct bandgap properties. The motion of carriers in quantum dots is limited in three dimensions, so a special energy band structure is produced and many unique physical effects are brought about, which have attracted increasing attention in recent years. Compared with traditional quantum well active regions, lasers using quantum dots as active region materials have the advantages of higher gain, lower threshold current and longer service life. There are many types of III-V quantum dots, and indium arsenide quantum dots have attracted widespread attention due to their unique properties. Indium arsenide is a direct bandgap material with very high radiation recombination luminescence efficiency. At the same time, the lattice mismatch between indium arsenide and gallium arsenide is 7.2%, which is easy to realize Stranski-Krastanov (S-K) growth mode in molecular beam epitaxy. In addition, the room temperature luminescence wavelength of indium arsenide quantum dots can be artificially regulated, which can cover the entire 1.3 μm band, which is in the optical fiber communication window, and thus has great application potential in optical communication.

[0004] At present, the active region of indium arsenide quantum dot laser basically adopts Dot-in-Well (DWELL) structure, which is composed of two layers of indium gallium arsenide and indium arsenide quantum dots wrapped in the middle. Through this structure, the emission wavelength of indium arsenide quantum dots can be adjusted to 1.3 μm band. There are two methods for adjusting the emission wavelength of indium arsenide quantum dots at present, including changing the deposition thickness of quantum dots and changing the composition of indium gallium arsenide. Both methods have their own shortcomings. The method of changing the deposition thickness of quantum dots has limited ability to adjust the emission wavelength of quantum dots, and with the increase of the deposition thickness, a large number of defect points will be introduced, which will affect the light emitting performance of the material and the service life of the device. The method of changing the composition of indium gallium arsenide needs to adjust the growth speed of the three groups, which consumes time to calibrate the growth speed and the composition of the material, and also needs to optimize the growth conditions such as growth temperature and deposition thickness, which consumes more machine time. If a method can be developed to adjust the emission wavelength of quantum dots in a large range by changing only one parameter, without changing other growth parameters and without bringing negative effects to the performance of the material, it will have great significance for scientific research and enterprise production. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a method for adjusting the emission wavelength of indium arsenide quantum dots by using arsenic pressure. The method has the advantages of: 1. large wavelength adjustment range; 2. wide adaptability; 3. convenient application; 4. accurate and reliable, which has important significance for adjusting the emission wavelength of quantum dots in practical application.

[0006] The present application provides a method for adjusting the emission wavelength of indium arsenide quantum dots by using arsenic pressure, comprising the following steps:

[0007] (1) changing the opening degree of the arsenic source furnace valve, and measuring and drawing the opening degree-beam current curve during the changing process;

[0008] (2) fixing the sample growth temperature, and growing a batch of quantum dot samples with different arsenic pressures according to the opening degree-beam current curve;

[0009] (3) measuring the photoluminescence spectrum of the batch of samples to obtain the peak emission wavelength information, and constructing the beam current-peak emission wavelength curve;

[0010] (4) calculating the required arsenic pressure for the target wavelength according to the beam current-peak emission wavelength curve.

[0011] Further, with the increase of the opening degree of the arsenic source furnace valve, the emission wavelength of the sample moves to the long wave direction.

[0012] Further, the peak emission wavelength of the sample grown at different arsenic pressures at the same temperature is different, the emission wavelength of the sample grown at increased arsenic pressure is red shifted, and the emission wavelength of the sample grown at decreased arsenic pressure is blue shifted.

[0013] Advantageous effects

[0014] The present application utilizes the rule that the wavelength of the indium arsenide quantum dot light emission changes with the arsenic pressure, and obtains the arsenic pressure required by the indium arsenide quantum dot sample with the target light emission wavelength by analyzing the measured arsenic pressure-peak light emission wavelength curve. The advantages are: 1. large wavelength adjustment range; 2. wide adaptability; 3. convenient application; 4. accurate and reliable, which has important significance for regulating the light emission wavelength of quantum dots in practical application. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The valve opening-beam current curve diagram obtained by increasing the valve opening of the arsenic source furnace in Example 1;

[0016] Figure 2 The infrared fluorescence emission spectrum diagram obtained by measuring the spectrum after growing a batch of quantum dots by changing the arsenic pressure in Example 1, the samples are grown at an interval of 75nA in the low arsenic pressure section, and the samples are grown at an interval of 100nA in the high arsenic pressure section and data is collected;

[0017] Figure 3 The beam-peak light emission wavelength curve diagram obtained by measuring the spectrum after growing a batch of quantum dots by changing the arsenic pressure in Example 1, the vertical axis of the diagram is the peak light emission wavelength, and the horizontal axis is the beam current value, the samples are grown at an interval of 75nA in the low arsenic pressure section, and the samples are grown at an interval of 100nA in the high arsenic pressure section and data is collected;

[0018] Figure 4 The infrared fluorescence emission spectrum diagram of two samples (A, B) grown by changing the arsenic pressure to 575nA in Example 1, the peak light emission wavelengths are 1309.7nm and 1311.3nm respectively. DETAILED DESCRIPTION

[0019] The present application will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and not used to limit the scope of the present application. In addition, it should be understood that after reading the content taught by the present application, those skilled in the art can make various modifications or changes to the present application, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

[0020] Example 1

[0021] The embodiment adopts a solid source molecular beam epitaxy (SSMBE) system, which has two solid V group sources of As and Sb, and three III group sources of Ga, Al and In. The MBE system can be used as an experimental device and a small-scale production device. The MBE system can epitaxially grow one 4-inch substrate, one 3-inch substrate or three 2-inch substrates at a time, and can realize fully automated operation.

[0022] Firstly, the arsenic beam current at different valve openings was measured by continuously increasing the valve opening from 20% to 100% at an interval of 5%. Figure 1 The arsenic source furnace valve opening-beam current curve determined by experiments. With the continuous increase of the valve opening, the arsenic beam current continuously increases and finally tends to saturation, the whole curve conforms to the theoretical relationship, the beam current size at low and high valve openings is obviously different, and the source furnace is suitable for experiments of changing arsenic pressure. After obtaining the relationship between the beam current size and the valve opening, the sample growth temperature is determined as 618°C, the quantum dot deposition thickness is 2.7ML, and the quantum dot stacking layer number is 5. On this basis, by changing the valve opening, quantum dot samples are grown at arsenic pressures of 325nA, 400nA, 475nA, 575nA, 675nA and 775nA respectively. During the whole growth process, except for changing the arsenic pressure when growing quantum dots, 775nA of arsenic pressure is used when growing other regions.

[0023] After the growth is completed, the sample is measured by a Thermo Scientific Nicolte iS50 Fourier infrared spectrometer. Figure 2 and Figure 3 The spectrum graph summary and the beam current-peak luminescence wavelength curve graph of different arsenic pressure samples are shown in FIGS. 1 and 2 respectively. After obtaining the infrared spectrum data of the sample, the peak luminescence wavelength is summarized and the relationship between the peak luminescence wavelength and the arsenic pressure is constructed. According to the relationship between the peak luminescence wavelength and the arsenic pressure, the arsenic pressure can be conveniently adjusted by using the curve to obtain a sample with a target peak luminescence wavelength. Taking the target peak luminescence wavelength 1310nm as an example, according to the curve obtained by experiments, it can be calculated that the corresponding wavelength when growing quantum dots at 575nA is 1310nm, and two samples are grown by using 575nA of arsenic pressure, and the peak luminescence wavelengths measured by the infrared spectrum are 1309.7nm and 1311.3nm respectively, which are located near the target peak luminescence wavelength. Figure 4 The two samples (A and B) with the target peak luminescence wavelength 1310nm grown by adjusting the arsenic pressure to 575nA by using the curve relationship are shown in FIGS. 3 and 4. Figure 3 As can be seen, by using this technology, the arsenic pressure can be accurately and conveniently adjusted to make the quantum dots reach the target peak luminescence wavelength, and the repeatability is good.

Claims

1. A method for controlling the luminescence wavelength of indium arsenide quantum dots by adjusting arsenic pressure, comprising the following steps: (1) changing the valve opening of the arsenic source furnace, measuring and drawing the opening-beam current curve during the change, and verifying whether the arsenic source furnace is suitable for changing the arsenic pressure according to the opening-beam current curve; (2) fixing the sample growth temperature, changing the valve opening of the arsenic source furnace, and growing a batch of quantum dot samples with different arsenic pressures; (3) measuring the photoluminescence spectrum of the batch of samples to obtain peak luminescence wavelength information, and constructing a beam current-peak luminescence wavelength curve; (4) calculating the required arsenic pressure for the target wavelength according to the beam current-peak luminescence wavelength curve.

2. The method of claim 1, wherein: With the increase of the valve opening of the arsenic source furnace, the luminescence wavelength of the sample moves towards the long-wave direction.

3. The method of claim 1, wherein: The peak luminescence wavelength of samples grown at different arsenic pressures at the same temperature is different, the luminescence wavelength of samples grown at increased arsenic pressure is red-shifted, and the luminescence wavelength of samples grown at decreased arsenic pressure is blue-shifted.

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