扫描开尔文探头可以测量 CPD（接触电位差）值，评估半导体和导电材料的功函数。测量不仅可以在样品表面的单点进行，还可以对整个表面进行扫描。

功函数测量在半导体物理学中特别有用，因为它提供了被测材料费米级的位置。

配备光源的开尔文探针可以检测样品的电子表面状态。电子的表面状态在电荷转移中起着重要作用，这对光伏材料和光电化学尤其重要。

通过扫描样品表面并检查其电学特性，可以精确评估材料的质量及其均匀性。 实验过程中收集的一系列数据可用于更精确地评估工作功能。

静电电压表

扫描式开尔文探头可确定被测样品表面（包括电介质）的静电荷分布！(最高可达几 kV）。该仪器采用的测量方法和设计使其在测试带电介质表面方面独一无二、无与伦比。该系统能够确定样品表面的静电荷分布（最高可达数 kV！）。

• 样品放置在 XY 工作台上的两个支架中的一个上。电动工作台可使样品在 X 和 Y 两个方向上移动 5 厘米： X 和 Y 方向移动 5 厘米。
• 每次探针接近被测样品时，都会精确测量样品表面与探针之间的距离，精度为 50 微米。在所采用的方法中，垂直轴的精度对于确定工作函数并不重要。
• 探头配有激光指示器，可在测量时照亮探头上方的一个点。光源有助于观察法拉第笼下的样品。
• 探头上方安装有光纤适配器。光纤可以用单色仪或 LED 左轮手枪发出的光照射样品。
• 在样品处理过程中，探针隐藏在金属盖下，可防止探针意外损坏。

探头尖端

探头尖端是完全由 Instytut Fotonowy 设计和制造的组件，它提供

• 即使距离样品上方 0.5 毫米，也能发出较大信号。 因此，样品表面是粗糙的还是抛光的并不重要。
• 让光线透过的透明度。 这样样品就可以被垂直光束照亮。

尖端振荡由电磁铁产生。

• 用于薄膜样品

法拉第笼

整个测量仪器由法拉第笼罩，使系统与周围环境隔绝。接地插座位于法拉第笼上。

规格

根据设备开发的进一步进程，以下规格可能会有所改变。

Voltage range	-5 V .. 5 V
Voltage measurement nominal resolution	0.15 mV
Measurement technology	2-channel lock-in amplifier
Sample holder	motorized translation stage X-Y,
Sample stand	stand for sample layer/ stand for solid state sample
Range of stage movement	5 cm x 5 cm
Min sample move step	1 µm
Tip type	Au, mesh, dia. 2.5 mm
Tip Z positioning	motorized Z stage
Positioning with respect to a sample	light barrier
Tip Z positioning resolution	10 µm
Spectral range for wave guides	200 nm .. 2000 nm (depending on a waveguide)
Liquid waveguides selection (Lumatec)
Auxiliary sensors	humidity and temperature
Internal Faraday cage illumination	white LED
X-Y positioning aid	laser sample placement indicator
PC connectivity	USB 2.0
Size	40 x 40 x 45 cm
Weight	15 kg

样品表面的电动势分布

测量时的环境温度

测量过程中的空气湿度

表面 CPD 评估值

样品表面的电动势分布

测量过程中的环境温度

测量过程中的空气湿度

铝箔上的聚四氟乙烯 – 来自样品表面电荷的电动势

Scanning Kelvin Probe allows to measure the Contact Potential Difference (CPD) not only in a single point of the sample but the entire sample surface may be scanned.
Kelvin Probe equipped with a light source enables to examine surface states of electrons in the sample. Surface states of electrons play a significant role in electric charge transfer, which is especially important for photovoltaic materials and in photoelectrochemistry.
Possibility of scanning the sample surface and to examine its electrical properties enables precise assessment of the quality of the material, its homogeneity, etc. The series of CPD values collected for many points of the sample, may be used to evaluate Work Function more precisely.

Electrostatic Voltmeter

The measurement technique, analytic methods applied and the design of the instrument makes the instrument unique and peerless in testing charged dielectric surfaces, including dielectrics where the measured potential above the accumulated charges may be as large as several kilovolts!

Scanning Kelvin Probe system enables to investigate:

• The Work Function of a material,
• Position of Fermi level with respect to the conduction and valence band edges,
• The type, n or p, of a semiconductor,
• Energy gap of a semiconductor,
• Surface potential (SPV by flat band technique),
• Surface adsorption and chemisorption effects on the Work Function,
• Information on the surface states density,
• Surface charging and discharging effects,
• Minority carriers diffusion length,
• Carrier recombination rates (especially for indirect bandgap semiconductors),
• Information on buried interfaces,
• Temperature influence on the Work Function,
• Humidity influence on the Work Function,
• Electrostatic charge distribution over the surface.

The Kelvin Probe set consists of:

• Controller unit,
• Kelvin Probe instrument with the Probe Tip,
• Faraday Cage.

The Kelvin Probe instrument is equipped with:

• Protective bay to park the Probe Tip after experiment,
• Laser pointer to indicate the area directly,
• Light source that helps to handle the sample when the instrument is covered with the Faraday Cage,
• Laser barrier to precisely detect the Probe Tip distance to the sample,
• Golden Probe Tip,
• Sample holder,
• Motorized XY Table.

Probe Tip

The most important part of the Kelvin Probe instrument is the Probe Tip.  The reference electrode is made of Au mesh of 2.5 mm diameter. It provides high signal to noise ratio, even from a distance of 0.5 mm above the sample. Thus, it does not matter if the examined sample surface is rough or polished. The tip oscillations are generated with an electromagnet.

The Probe Tip is the component fully designed and manufactured by Instytut Fotonowy Sp. z o.o.

• Bottom contact stand for samples on conducting substrates,

Faraday Cage

The entire instrument is covered with the Faraday Cage, shielding the setup from the ambient light and electromagentic fields.

Gas-tight Faraday Cage with inert gas flow system

Scince measurements of the CPD is often sensitive to environmental factors like temperature, humidity, dust and chemical contaminants, Kelvin Probe may be placed inside the hermetic version of the Faraday Cage with the inert gas flow system.

Laser barrier

The Kelvin Probe is equipped with the Laser barrier system. System automatically detects the sample sub-
strate. Each time the probe approaches the sample being examined, an accurate distance between the sample surface and the Probe Tip is measured with 20 µm precision.

Sample illumination

The sample may be illuminated during the measurements from the optical fiber situated above the Probe Tip. The Probe Tip lets the light through. The light at optical fiber input may be provided by the LED Revolver, Xenon Lamp combined with the Monochromator or any other type of the light source desired.

General:

• Weight: 10 kg,
• Size: 40x40x45 cm,
• PC connectivity: USB 2.0,
• Power supply: 230 V, 50 Hz or 115 V, 60 Hz,
• Measurement technique: 2-channel lock-in-amplifier,
• Laser barrier to automatically detect the substrate and prevent the tip from running into the sample,
• Auxiliary sensors: humidity, temperature,
• Small lamp,
• Laser pointer for examined point of the surface indication,
• Sample holders:
  – Freely shaped solid state with top contact holder,
  – Bottom contact holder,
  – Electrochemical holder,

Faraday Cage:

• Standard / gas-tight with inert gas flow system,

Distribution of the electric potential on the sample surface:

Ambient temperature during measurement:

Air humidity during measurement:

Evaluated CPD values on surface:

Distribution of the electric potential on the sample surface:

Ambient temperature during ongoing measurement:

Air humidity during ongoing measurement:

PTFE on alluminium foil – Electric potential from the surface charge of the sample