Product keywords: surface photovoltage SPV, surface photospectrum SPS, phase spectrum, surface photocurrent SPC, SPV, SPC, SPS, surface inspection technology, energy band diagram, interface and defect states, surface potential, diffusion length, minority carrier lifetime, surface space charge, minority carrier lifetime
▌ Product introduction
SteaPVC is a steady-state surface photocurrent/photovoltage measuring instrument launched by Orienlal Spectra(hereinafter referred to as 0S) for photoelectric fields such as photocatalysis, semiconductor, and MOF (Metal-Organic Framework). SteaPVC is the sister product of TranPVC (Transient photocurrent/Photovoltage/Photocharge measuring instrument), which together provides the industry with a complete product solution for stable, transient photocurrent, photovoltage and photocharge measurement. SteaPVC is developed based on phase-sensitive detection technology, which can detect ultra-weak steady-state photocurrent and photovoltage signals under different excitation wavelengths. Integrated with a variety of measurement modes, wavelength dependent photocurrent spectrum, photovoltage spectrum and phase spectrum can be easily obtained. It is equipped with a visual automatic sampling system, which can easily visually control the position of the sample, and has a high degree of automation and integration, which fully reflects the product concept of 'one-click power on, one-time loading, global measurement and real-time interaction' of Oriental Spectra Technology.
Surface photovoltage (SPV) is a widespread physical phenomenon in semiconductors. surface photovoltage spectroscopy (SPS) is the detection of semiconductor device samples in a non-contact, non-destructive manner. The band gap, surface potential, oxide layer, minority lifetime, diffusion length, interface and defect state, energy band Offset of quantum well structure are studied. SteaPVC also has an optional module for photocurrent spectrum, which constructs a special detection current loop for samples with photocurrent effect to form photocurrent, thus obtaining photocurrent spectrum. SteaPVC uses the Melal-insulalor-semiconductor(MIS) method to test samples, which is a non-destructive test method and simple sample preparation. In recent years, SPS methods have been greatly developed in silicon-based semiconductors, III-V compound semiconductors, perovskites, organic semiconductors, photocatalysis, hydrolyzed hydrogen and other industries.
SteaPVC is the industry's first commercial, automated surface photovoltage/photocurrent measuring instrument, bringing a revolutionary experience to users. It achieves a high degree of automation, almost all operations can be completed automatically, eliminating manual tedious steps, so that users can easily get started without professional background. Secondly, its data accuracy is extremely high, and it can provide users with accurate and reliable analysis results, which greatly improves work efficiency. In addition, the device is very easy to use, and users can quickly set up and start working after half a day of training. Its interface design is intuitive and clear, and even beginners can quickly grasp the operation method. This instrument not only liberates the professional bondage of users, but also wins the love of users with its efficient and accurate characteristics, helping users to easily cope with a variety of complex SPS test tasks.
SPS is a kind of interface detection technology. In general, a surface is defined as the boundary of a medium with different physical properties. For example, the surface between a semiconductor and a vacuum or gas is called a 'free surface,' or just a 'surface.' The surface between a semiconductor and another solid is often referred to as the 'interface.' However, we sometimes use the term 'surface' to mean any boundary, i.e. the generalized surface is the interface. SPS can be used to study the properties of semiconductor surface, interface and body.
Surface-localized states are the main causes of Surface photovoltage generation. There are many physical sources who can form surface localized states, such as: 1) local electronic states generated in the energy gap due to periodic failure; 2) a dipole layer is formed on the surface; 3) Breakdown of lattice symmetry; 4) Surface recombination to minimize surface energy; 5) The surface forms a suspension key; 6) Surface adsorbed impurity layer, etc. These surface localized states trigger charge transfer between the interior of the material and the surface to establish a thermal balance between the two, forming a non-electrically neutral region of space charge. This is the main cause of surface photovoltage. When detecting SPS, it involves the use of carefully modulate detection light to interact with the sample, and then detect the surface photovoltage changes in light and non-light, to obtain a signal of the surface photovoltage: Vspv = Vs(light)−Vs(dark), the signal is usually extremely weak, and it is difficult to test the general detection device.
SteaPVC uses advanced optical signal modulation technology to significantly improve the ability to capture and identify weak electrical signals, so that useful signals can be effectively extracted from the background noise, thereby enhancing the signal-to-noise ratio of the signal to ensure the accuracy and repeatability of the detection results. In terms of hardware design, SteaPVC has fully considered the issue of electromagnetic compatibility (EMC) and adopted a variety of measures to suppress possible electromagnetic interference. This design makes the equipment not only resistant to external electromagnetic interference, but also reduces the electromagnetic radiation generated by the equipment itself, ensuring the high sensitivity and stability of the instrument. Based on the analysis of the measured data obtained by SteaPVS, combined with the actual physical model process of the sample, users can study a series of physical characteristics, including the characteristics of the semiconductor surface, and can obtain the property parameters of the semiconductor material body. Some common related physical parameters are as follows:
1. Surface and interface related properties:
① Band map
② DOS of surface states
③ Trap states/defects (gap states)
④ Surface oxidation thickness
⑤ Band-offsets
⑥ Surface Space Charge Region (SCR)
⑦ surface dipole: surface dipole
⑧ Tail states
2. At the same time, a lot of quantitative information related to the nature of the ontology can be obtained:
① Band gap;
② Conduction type;
③ diffusion length;
④ minority carrier lifetime;
▌ Measurement mode
□ Single point measurement;
□ Scanning measurement：
Wavelength scanning;
Frequency scanning;
Light source intensity scanning;
Electric field intensity scanning (EFISPS);
Temperature scan: variable temperature test.
▌ Product characteristics
□ Turn-key system, with full 'Plug & Play' features;
□ Rich function of setting test conditions;
□ It has the characteristics of automation and high integration;
□ The test process is controlled by software, easy to use, low requirements for professional skills of operators;
□ The sample table has displacement function, which is convenient to test different sub-devices on the same substrate. The test switch of multiple sub-devices is carried out by software, and the test efficiency is high.
Integrated sample compartment, easy to replace the sample and electrical interconnection, sample compartment visual monitoring system, real-time observation of the test light irradiation device, easy to adjust the light spot irradiation position of the sample.
▌ Functional parameter
□ Surface photovoltage SPV;
□ Photocurrent spectrum (SPC, optional);
□ Electric field induced surface photovoltage spectrum (EFISPS, optional);
□ Pump - Probe surface photovoltage spectrum (PPSPS, optional);
□ Phase spectrum, etc.
▌ Product application
□ Suitable for silicon-based semiconductors, compound semiconductors, third-generation wide-band gap semiconductors, Wafer testing, organic solar cells, perovskite solar cells, organic light-emitting diodes, two-dimensional semiconductors, dye-sensitized solar cells, copper indium gallium selenium solar cells;
□ Applicable to MOF (metal-organic framework), COF (conjugated organic framework), cadmium zinc telluride (CZT), photolysis water, Mxenes, photocatalytic devices, other photoelectric conversion devices.
▌ Technical parameter
Surface photovoltage spectrometer /SteaPVC |
Feature | SPS | Standard configuration |
PIS | optional |
EFISPS | optional |
PPSPS | optional |
Wavelength range | 300-2500nm |
Minimum step wavelength | 0.01 nm |
Wavelength regulation mode | Auto |
Photovoltage range sensitivity | 1nV to 1V |
Voltage noise | 9nV/√Hz@997Hz； |
Dynamic reserve | 120dB |
Frequency range | 14Hz~700Hz or 20Hz~1kHz |
SPV automatic sample station | Yes |
Sample bin visualization system | Yes |
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