Extraction of source functions of surface photovoltage transients at very short times

Abstract

The measurement of surface photovoltage (SPV) transients over 12 orders of magnitude in time was recently demonstrated [Rev. Sci. Instrum. 88, 053904 (2017)]. In dedicated experiments, however, a high-impedance buffer shall be placed outside the measurement chamber, which has consequences for SPV measurements at very short times. By varying the LCR circuit of a measurement configuration, applying a multi-parameter fit and simulating the corresponding SPV transients, we show, on the examples of highly doped silicon and a CdS thin film, that the source function of SPV transients can be reconstructed with a resolution time better than 1 ns.

An Analytical Approach to CH3NH3PbI3 Perovskite Solar Cells Based on Different Hole Transport Materials

“…SPV is a powerful technique for the investigation, for example, of the mechanisms of charge separation and relaxation, of the electronic states and of their dynamics in photoactive materials such as powders for photocatalysts or as colloidal quantum dot . Modulated and transient SPV spectroscopy are done in the fixed capacitor arrangement and are sensitive to time scales of about 1 order of magnitude below or above the modulation period and of the order from ns and less or up to 10 3 s, respectively.…”

Modifying morphology and defects of low-dimensional, semi-transparent perovskite thin films via solvent type

“…4. Through the charge potential difference (CPD), 51,52 the n5 and n3 perovskites were determined to be p-type semiconductors, which could be identied by the negative SPV signals where photo-generated electron carriers were preferentially separated into the external interface, whereas the holes moved towards the bulk. 53 Intrinsic p-type doping was induced by the presence of lead vacancies (V Pb ), whereas n-type doping resulted from the presence of iodide vacancies (V I ) seen in PbI 2 rich lms.…”

Surface Photovoltage Spectroscopy over Wide Time Domains for Semiconductors with Ultrawide Bandgap: Example of Gallium Oxide

“…[16,17] Recently, for example, transitions and charge transfer processes were studied in c-Si/TiO 2 and CuBi 2 O 4 heterojunctions by transient [18] and modulated [19] SPV spectroscopy, respectively, and the bulk photovoltaic effect has been shown for excitation from defect states in carbon-doped GaN. [20] Incidentally, one SPV spectrum has been shown for Ga 2 O 3 in the work of Gao et al, [15] but in our opinion, the signal-to-noise ratio was insufficient to extract energy levels in a reliable manner.Fast and robust SPV measurements are carried out in the fixed capacitor arrangement [21] for achieving short resolution times (below 1 ns, [22] transient measurements) or high sensitivity (range of 100 nV, [23] modulated measurements). In the fixed capacitor arrangement, an electrode based on a transparent conducting oxide (TCO) and an insulating foil between the sample and the electrode are used for forming the measurement capacitor for capacitive out-coupling of SPV signals.…”

“…Fast and robust SPV measurements are carried out in the fixed capacitor arrangement [21] for achieving short resolution times (below 1 ns, [22] transient measurements) or high sensitivity (range of 100 nV, [23] modulated measurements). In the fixed capacitor arrangement, an electrode based on a transparent conducting oxide (TCO) and an insulating foil between the sample and the electrode are used for forming the measurement capacitor for capacitive out-coupling of SPV signals.…”