The laser power was additionally diminished due to coupling losses from fibre to fibre in the case of the probe station setup or via coupling through pinholes, reflection in mirrors and beam splitters in case of the confocal setup. For the electrical measurements a Keithley instruments 2636B sourcemeasure unit was taken for dark current and ON/OFF measurements. For the time-resolved measurements, a Zurich Instruments UHF Lock-In amplifier was used with a Periodic Waveform Analyzer function averaging over 2 G samples in combination with a transimpedance amplifier (FEMTO DHPCA-100) when necessary. The electrode pads were connected with 50 Ω matched tungsten probes and coaxial cables with bandwidths exceeding 1 GHz at the probe station. At the confocal setup, gold plated probe tips and triaxial probe holders (79-8000-T-03 Micromanipulator) were used to make contact beneath a custom build faraday cage. For connection between the triaxial cables and the BNC-input at the lock-in amplifier a triax(F)-to-BNC(M) connector (Pomona) was used, however, the manufacturer's bandwidth specifications were not provided. The bandwidths of the other devices are 600 MHz for the lock-in amplifier and 175 MHz for the transimpedance amplifier at an amplification of 10 3 .