Device for contactlessly determining the surface photovoltage and the photoemission current of an object to be examined, and method for contactlessly determining the surface photovoltage or the photoemission current of an object to be examined by means of the device

Abstract

The invention relates to a device (100) for contactlessly determining the surface photovoltage (USPV) and the photoemission current (i) of an object (2) to be examined, wherein the device (100) comprises: an electrically conductive surface (1) on which the object (2) to be examined can be positioned; a voltage source (5) which is designed to generate an electrical potential in the electrically conductive surface (1); an electrode (3) which is situated opposite the electrically conductive surface (1) such that the object (2) to be examined, when positioned on the electrically conductive surface (1), is located between the electrically conductive surface (1) and the electrode (3); a transimpedance amplifier (TIA), the input (21) of the transimpedance amplifier (TIA) being connected to the electrode (3) and the output (22) of the transimpedance amplifier (TIA) being connected to a surface photovoltage signal output (9) on which an output voltage (UA) can be measured, the output voltage being output by means of the transimpedance amplifier (TIA) and being indicative of the surface photovoltage (USPV) of the object (2) to be examined; and a frequency response correction device (10) for at least partly compensating for a frequency response drop of the output voltage (UA) of the transimpedance amplifier (TIA), the output voltage additionally being indicative of the photoemission current (i). An input (31) of the frequency response correction device (10) is connected to the output (22) of the transimpedance amplifier (TIA), and an output (32) of the frequency response correction device (10) is connected to or forms a photoemission current output (11) on which the at least partly frequency response-compensated output voltage (UA) can be measured. The invention further relates to a method for contactlessly measuring the surface photovoltage (USPV) and to a method for contactlessly measuring the photoemission current (i) of an object (2) to be examined by means of the device (100).

Description

[0001] 03-09-2025-4370900 -H au P Pc -0045PCT / DE2025 / 000094 Device for non-contact determination of surface photovoltage and photoemission current of a test object and method for non-contact determination of the surface photovoltage or photoemission current of a test object. Description: Surface photovoltage and photoemission current method. The surface photovoltage of the test object, as well as the method for determining the photoemission current, are of particular importance for the investigation of thin surfaces. These quantities are subject to optimization and new measurement methods. However, the apparatus for recording these quantities does not guarantee that the samples to be investigated will be different from the measuring apparatus. The process also requires specific conditions for measurements.which results various measuring instruments also the of measurement deviations and complicated and the DE 10 2019 117 989 B3 non-contact voltage measurement. This concept field mill and is designed to record AC and surface tension measurement. The sum signal is connected to an output and / or an amplifier output, whereby the amplifier voltage is at least such that the cutoff frequency of less than 10 is reached via the output and a second output regulator voltage is connected to a summing amplifier, whereby the amplifier voltage from the and regulator voltage is added to the output voltage and output voltage. 03-09-2025-43703001 -HauP tPes t-0046 2 US 5,393,980 OSEE), the external impurities of surfaces are determined. In addition, an electromechanical Kelvin probe is used to determine the surface. The results of OSEE measurements,Kelvin probe and sample oscillation, whereby current which is caused by voltage. This voltage is used in the method for determining the surface recombination lifetime constant of EP 0 656 643 A1. A contact is arranged with the counter electrode. Furthermore, the measuring probe excites photocurrents, whereby the measuring probe detects the measurement signal. The starting task is based on...The task is to provide both the surface photovoltage and the photoemission current of the object under investigation. This method is designed to measure the surface photovoltage and the photoemission current of the object under investigation. These tasks are achieved by the features of claim 8 and the features of claim 10. The embodiments of the invention are specified in the corresponding dependent claims and are described below. The aspect of the surface photovoltage and photoemission current of the object under investigation is: □3-09-2025-43709001-HauP«tP Os ^-0047PCT / DE2025 / 000094. A voltage source is provided for generating the surface, arranged opposite the surface, such that when it is arranged between the surface and the surface, a transimpedance amplifier is arranged.where the input of the transimpedance amplifier and the output of the transimpedance amplifier are connected to a surface photovoltage signal output, at which output voltage of the transimpedance amplifier can be measured, which surface photovoltage of the object under investigation, and at least compensation of the frequency response drop, the photoemission current, output voltage of the transimpedance amplifier.where input is connected to the output of the transimpedance amplifier and output is connected to a photoemission current output or at which at least a frequency-compensated output voltage can be measured. Output voltage UA of the transimpedance amplifier. Relationship UA = USPV*(-CL / C(8)) Surface photovoltage of the object under investigation where CL of the medium between the object under investigation and the feedback capacitor of the T. Output voltage UA of the transimpedance amplifier. Relationship UA also the photoemission current where resistance value of the feedback resistor of the transimpedance amplifier. Measurement bandwidth of the surface photovoltage depends on the of the transimpedance amplifier and can be in the MHz range. Frequency of the transimpedance amplifier = for R(7) = TQ and = pF = 0.16 and cutoff frequency. Accordingly, surface photovoltage signals are measurable above Hz. For the photoemission current, the object under investigation uses a voltage source with voltages of V and -300, and the surface photovoltage is measured. 03-09-2025-43709001-Hau pPo t-0048 4 differing measured quantity now from the object of investigation of the photoemission current. from and resulting frequency of Hz this upper measurable cutoff frequency. Correspondingly, photoemission current signals frequency range of Hz Hz measurable. In particular, according to the invention, the frequency response fall-off of the photoemission current output voltage is at least preferably compensated so that both surface photovoltage and photoemission current of the object of investigation are frequency response compensated. This compensation via frequency-dependent adjustment of the gain of the photoemission current output voltage of the transimpedance amplifier is frequency response compensated from the output voltage of the transimpedance amplifier output at the photoemission current output according to the gain. The object of investigation can be arranged in the sense that the object of investigation is on the surface. Correspondingly, the object of investigation can be arranged in the opposite direction to the surface. However, the object of investigation can also be applied to the surface.contrary to the surface, spaced accordingly so that the object under investigation is located between the surface and the surface of the object under investigation, so that the object under investigation receives a voltage source relative to ground. Preferably, according to the embodiment according to the invention, it consists of a feedback resistor and a feedback capacitor of the transimpedance amplifier. The frequency of the transimpedance amplifier is preferably a maximum of Hz or exactly Hz, and the frequency-independent gain is 03-08-2025-43708001-HauPiPcs 4-00485. The gain or the frequency response of the transimpedance amplifier is naturally dependent on the photoemission current. According to the embodiment according to the invention, the gain increases above the frequency, in particular by 20 dB per decade, compensating for the frequency response drop. The output voltage of the transimpedance amplifier is at least preferably determined by the embodiment according to the invention.The gain above the frequency is again frequency-independent, whereby the frequency is at least by the frequency, preferably by the frequency. Accordingly, without exceeding the signal-to-noise ratio by more than two decades, dimensioning according to 1 and frequency-dependent gain V2 = 100*V1 is possible. In the photoemission current signals, a frequency response of 0 Hz 16 is obtained, so that one can also obtain frequency of the transimpedance amplifier at a maximum, preferably a maximum of Hz or exactly Hz, and frequency-independent and frequency-increasing gain, in particular 20 dB decade-increasing gain, which above the frequency is again frequency-independent, whereby the frequency exceeding the frequency is at least by the frequency, preferably by the frequency. According to the embodiment according to the invention, in particular, where between and 5 above the gain is at least 20 dB decade, preferably 60 dB - 100 dB decade, this of the measurement signals can be more than broadband noise. Grade 03-09-2025-4370S001“HauPfPos^-0050 6 According to the embodiment according to the inventiona distance of 10 mm between the surface or arranged so that test objects of several mm can be arranged between and the surface and between mm and mm of the pointing of the test object spaced several mm" is referred to in connection with thicknesses of test objects of between mm and 10 mm. In particular, of mm and 10 mm. According to an embodiment of the invention, at least in particular at openings electromagnetic the test object is arranged, in particular wherein holes the electromagnetic of a further embodiment of the invention and / or surface such that and surface and when the test object of the surface as well as between the surface and the test object, and the test object, is movable relative to each other. In particular, relative movement at least spatial component, in particular the distance direction between and the distance direction can be given by an axis, the distance vector between and surface which is either the orThe surface is used to generate relative motion between the surface and the object under investigation by moving the surface. However, it can also be coupled to the surface to generate both movement and relative motion between the surface and the object under investigation. It can also comprise several, in particular two, surfaces, so that the surface can also be moved. 03-09-2025-43709001-HauP*Posi-0051 7 Relative motion between the surface and the object under investigation. DC voltage component. Surface photovoltage of the object under investigation. According to an embodiment of the invention, electromagnetic, which is used to generate electromagnetic, can then be used to generate the surface photovoltage or the photoemission current of the object under investigation. Aspect: Method: Surface photovoltage of the object under investigation according to the aspect: According to this method, the object under investigation is arranged on the surface and between the surface and the electromagneticwhere the output voltage of the transimpedance amplifier is measured at the surface photovoltage signal output, which surface photovoltage of the object under investigation. According to the embodiment of the method, the object under investigation is moved relative to each other and is compensated by AC voltage from the voltage source. The DC component of the surface photovoltage of the object under investigation is used. In particular, the movement and direction of the distance between the object and the surface photovoltage of the object under investigation are measured. In particular, relative movement between the object and the surface photovoltage of the object under investigation can be measured, or at least in the direction of approach between the object and the surface photovoltage of the object under investigation during the AC component of the output voltage of the transimpedance amplifier. The DC component of the surface photovoltage of the object under investigation can also be measured at this frequency of the voltage from the voltage source.The object under investigation and the voltage source can be such that the AC component output voltage of the transimpedance amplifier is measured in magnitude. The aspect of the photoemission current method of the object under investigation is determined according to the aspect of the surface. According to this method, the object under investigation is measured on the surface and between the surface and the voltage source of the surface and the object under investigation, and the frequency response drop is at least compensated for the photoemission current of the object under investigation. The output voltage of the transimpedance amplifier is measured at the photoemission current output. In the following, characteristics and features are measured based on the aspect of the 2 measured spectra of the photoemission current and surface photovoltage signals of the object under investigation. 2 p-type spectra and 3 DC photoemission and DC surface photovoltage signals of the p-type in a vacuum. 100 Surface photovoltage USPV and photoemission current of test object 2 according toThe aspect 100 includes the surface of which the object under investigation can be used to generate a voltage source. Through contact between the surface and the object under investigation 2, the object under investigation 2 can be connected to ground via voltage source 5. Ö3-08-2025-43703001-HauP tPost -00E3 9 100 arranged relative to the surface 3 so that the object under investigation 2 can be connected between the surface and the surface by electromagnetic 4. The object under investigation is connected to a surface photovoltage USPV photoemission current of 100. The surface of the object under investigation 2 and 3 is shown in a 100 designated SQ. The 100 transimpedance amplifier TIA has a feedback resistor and a feedback capacitor 8. The input of the transimpedance amplifier TIA and the output 22 of the transimpedance amplifier TIA are connected to a surface photovoltage signal output 9, at which the transimpedance amplifier TIA receives a signal.Output voltage UA measurable. This output voltage UA is measured via the relationship UA = USPV*(-CL / C(8)) surface photovoltage USPV of the object under investigation 2, such that the surface photovoltage USPV can be measured by measuring the output voltage UA of the transimpedance amplifier TIA. The negative feedback capacitor 8 of the transimpedance amplifier TIA and CL of the medium between the object under investigation 2 and the surface photovoltage USPV of the object under investigation 2 can be assumed to be 100. For the photoemission current, 100 also includes at least 10 for compensation of the frequency response drop. The photoemission current output voltage UA of the transimpedance amplifier is measured via the relationship UA, where the resistance value of the negative feedback resistor 7 of the transimpedance amplifier TIA is connected. Input 10 is connected to output 22 of the transimpedance amplifier TIA, and output 32 is connected to a photoemission current output, at which at leastFrequency response compensated output voltage UA measurable. Accordingly, the 100 can also be the photoemission current of the object under investigation 2. 03-09-2025-43703001-HâuP tPos t-0054 10 A frequency of the transimpedance amplifier TIA from the feedback resistor and the feedback capacitor 8 of the transimpedance amplifier TIA frequency of the transimpedance amplifier TIA maximum preferably As indicated in 10, the frequency-independent gain above frequency in particular 20 dB decade, to frequency gain again frequency-independent frequency at least by the preferably by greater frequency that frequency above gain at least 20 dB decade, preferably 60 dB - 100 dB decade, preferably between and 100 dB. Method surface photovoltage USPV of the object of investigation 2 according to the second aspect as well as method of the photoemission current of the object of investigation according to the aspect of For the method of surface photovoltage of the object of investigation 2 according to the aspect the object of investigation of the surface and between theSurface and 3 Subsequently, the electromagnetic 4 and surface photovoltage of the object under investigation are measured at the surface photovoltage signal output 9. This includes at least 100 which and / or the surface are coupled so that 3 and the object under investigation can be moved relative to each other. Thus, the method of measuring the surface photovoltage of the object under investigation can be used in accordance with the aspect of the relative movement between the surface and the object under investigation by compensating for the AC 3 voltage source 5 DC voltage component surface photovoltage USPV of the object under investigation. 03-09-2025-43709001-HauP Pos i-0055 PCT / DE2025 / 000094 of surface photovoltages USPV or 4 between and the object under investigation as well as the feedback capacitor 8 of the transimpedance amplifier TIA are gain-determining. In the present case, the relationship between and the object under investigation is assumed to be CL. For or changesSurface photovoltage USPV of the object under investigation, whose frequency components above the frequency and output voltage UA of the transimpedance amplifier TIA as before UA = USPV*(-CL / C(8)), where the measurement bandwidth of the feedback capacitor 8 depends on the 6 of the transimpedance amplifier TIA and can be in the MHz range. Frequency of the transimpedance amplifier TIA = where the resistance value of the feedback resistor 7 of the transimpedance amplifier TIA = TO and pF = and cutoff frequency. Accordingly, surface photovoltage signals above Hz are measurable. This cutoff frequency is chosen to allow even slow surface photovoltage transients to be measured with low distortion. Surface photovoltage signals are measured at the output of the transimpedance amplifier TIA. Output voltage UA. Furthermore, very slowly changing surface photovoltage signals can also be measured by switching to the DC regime, in which the movement and the AC voltage source are adjusted.Change in voltage DC component of the surface photovoltage USPV. For the method of the photoemission current, the object under investigation is measured according to the aspect of the object's surface and between the surface and 3. Subsequently, voltage source 5 of the surface and the object under investigation 2 and 10 frequency response drop to this photoemission current output voltage UA transimpedance amplifier TIA at least. The photoemission current 03-09“2Ö25-43709001-HauP4P st“0056 via at least frequency response compensated output voltage UA at the photoemission current output 1. Accordingly, the object under investigation 2 is biased by voltage source 5, voltages in the range of V and -300 and the surface photovoltage is a different measured quantity. Now, the output voltage UA of the transimpedance amplifier TIA UA = off and the resulting frequency of Hz is now the upper limit frequency. Accordingly, photoemission current signals are measurable in the frequency range of Hz.This can be very important, especially when the electromagnetic frequency response is reduced by 20 dB per decade. The transimpedance amplifier TIA can achieve this without affecting the signal-to-noise ratio. The dimensioning can be adjusted according to the formula V2 = 100*V1, and the frequency-dependent gain V2 = 100*V1 can be achieved over two decades. For measuring photoemission current signals, a frequency response of 16 is now obtained, allowing for the measurement of broadband noise above 50 Hz. For reading out A / D converters, the broadband noise above this frequency can be reduced. This is generally more effective than a low-pass filter, which can reduce mains hum components of 50 Hz and 100 Hz from ambient lighting. A gain of over 20 dB per decade, preferably 60 dB - 100 dB per decade, is used. Photoemission current signals are fed to the output voltage UA at output 32, which is at least frequency-response compensated. The separate routing of theSurface photovoltage USPV, namely output voltage UA of the transimpedance amplifier TIA 03-09-2025-43703001-Haup Pos +-0057 PCT / DE2025 / 000094 13 Frequency response correction device 10 and the photoemission current form at least frequency response compensated output voltage UA according to the 10 convenient In addition, switching on the transimpedance amplifier TIA between the surface photovoltage or photoemission current measurement regimes is necessary and it can result in large very high frequencies of the surface photovoltage USPV and the photoemission current. One obtains surface photovoltage or photoemission current measurement signals with low noise and frequency responses. Measured spectra of photoemission current and surface photovoltage signals of the object under investigation, p-type form, such object under investigation 2, characterized by a particularly high surface density of states and resulting in particularly distinctive photoemission current and surface photovoltage signal spectra measurements. In this sense, the object under investigation usedSeparation of AC photoemission current and AC surface photovoltage signals. Spectra output voltage UA of the transimpedance amplifier, where the surface photovoltage USPV can be measured at output 22 of the transimpedance amplifier TIA or at the surface photovoltage signal output, and the photoemission current at least a frequency-response-compensated output voltage UA at the photoemission current output at output 32. 10 2 correspond to in-phase and phase-shifted modulation period or slow. Furthermore, it is noted that during the rise and fall of the signal and the switch-off of the signal, in-phase and phase-shifted signals have opposite signs. In contrast, the in-phase and phase-shifted photoemission current signals have opposite signs when there is a sign change during the fall-off. The signs of the in-phase and phase-shifted photoemission current signals of eV have opposite signs. 03-09-2025-43703001-Hau? iPos -0058 PCT / DE2025 / 000094 14 phase-shifted thePhotoemission current signals. In contrast, in-phase and phase-shifted signals between approximately eV and eV show different signs. Illumination around the surface, preferably without, but from the object under investigation 2 (charge carrier separation), illumination through the space charge boundary layer of the object. Switching off the illumination from a near surface to the volume of the object, the sign of the photoemission current spectra can be assigned to areas of the photoemission current spectrum. The signs of in-phase and phase-shifted signals between approximately eV and eV are the opposite of the SPV signals, where the surface is excited by the photons and charge separation occurs after switching off the light. In contrast, in-phase and phase-shifted signals above eV mean that high photon energies permanently excite the sample and thus generate increased photoemission.Vacuum chamber, so that the excess charge near the sample surface is switched off and the surface photovoltage is reversed, thus reducing the surface photovoltage. Consequently, regions of the SPV spectra can be assigned the sign of in-phase and phase-shifted photoelectron emission and charge separation. DC photoemission and DC surface photovoltage signals of the p-type photoelectron in vacuum. The photoemission current of the test object 2 was measured at voltage source 5 applied to the rear of the test object 2 at a voltage of -100 V. DC surface photovoltage signals were measured. Measurement 03-09-2025-43709001-Hau® *Pc s 4-0059 PCT / DE2025 / 000094 15 Relative motion between the test object and the photoemission current signals set photon energies of approximately eV and above eV due to the use of a monochromator. DC surface photovoltage signals set around eV and negative surface photovoltage signals of a p-type depletion layer. It DC-Surface photovoltage signals correspond to DC photoemission current measurements and vice versa.

[0002] 03-09-2025-43708001-HauP *Pusi-0060 16 Reference List Object of Investigation 2 Electromagnetic 4 Voltage Source 5 6 Feedback Resistor 7 Feedback Capacitor 8 Surface Photovoltage Signal Output 9 10 Photoemission Current Output 1 Input of Transimpedance Amplifier Output of Transimpedance Amplifier 22 Input Output of 32 100 Photoemission Current SQ Transimpedance Amplifier TIA Surface Photovoltage USPV

Claims

03-08-2025-43709001-HauPiPost-00S2 PCT / DE2025 / 000094 17 Claims Surface photovoltage and photoemission current of the object under investigation wherein - surface which is the object under investigation - voltage source to generate the surface, - arranged opposite the surface so that the object under investigation is positioned between the surface and the surface - transimpedance amplifier wherein the input of the transimpedance amplifier and the output of the transimpedance amplifier are connected to a surface photovoltage signal output at which the output voltage (UA) of the transimpedance amplifier is measurable which is the surface photovoltage of the object under investigation as well as - at least compensation of frequency response also the photoemission current output voltage (UA) of the transimpedance amplifier wherein the input is connected to the output of the transimpedance amplifier and the output is connected to a photoemission current output or at which at least frequency response compensatedOutput voltage (UA) measurable according to claim 1, wherein a feedback resistor and a feedback capacitor of the transimpedance amplifier provide a frequency of the transimpedance amplifier of a maximum of Hz and 03-08-2025-4370800 -HauP+Pe -0063PCT / DE2025 / 000094 18 frequency, frequency-independent gain and gain increasing above frequency, which above a second frequency becomes frequency-independent again, wherein the frequency is at least greater than the frequency according to claim 1, wherein the gain exceeding the frequency is at least 20 dB. A decade according to a preceding claim, wherein the surface can be arranged at a distance of 10 mm or arranged so that test objects of several mm can be arranged between the and the and spaced between mm and mm away from the facing of the test object according to a preceding claim, wherein openings are made by electromagnetic means. The test object is measured according to a preceding claim, wherein and / or the surface is arranged so that andSurface movable relative to each other according to a preceding claim, comprising electromagnetic devices which are used to measure the surface photovoltage of the object under investigation according to a claim, wherein the object under investigation is arranged between the surface and electromagnetic devices, and wherein the output voltage (UA) of the transimpedance amplifier is measured at the surface photovoltage signal output, which measures the surface photovoltage of the object under investigation. 03-09-2025-43709001-HauP Po i-0064 PCT / DE2025 / 000094 19 The method according to claim 1, wherein the surface and the object under investigation are moved relative to each other and the surface photovoltage of the object under investigation is compensated by the AC voltage of the voltage source and the DC voltage component. The method is based on the photoemission current of the object under investigation according to one of the claims, wherein the object under investigation is arranged between the surface and the DC voltage component, wherein the voltage source of the surface and the object under investigation is the photoemission current of the object under investigation, and wherein the frequency response drop at least compensates the output voltage (UA) of the transimpedance amplifier and is measured at the photoemission current output.

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