Effective-lifetime and reflectance measurements on a high-purity silicon wafer with surfaces passivated by aluminum-oxide layers

Effective-lifetime and reflectance measurements were done on a 725-μm-thick n-type silicon (Si) wafer with a resistivity in the range of 500 to 1200 Ω cm. A 25-nm aluminum-oxide layer was deposited onto each of the Si-wafer surface to reduce the surface recombination velocity.

The effective-lifetime data in Effective_lifetime_preliminary.rtf were taken through photoconductance-decay measurements with a Sinton WCT-120 life-time tester (see Applied Physics Letters 69, 2510 (1996) for the method).

Two reflectance measurements were done by using a continuous 314.4-GHz electromagnetic wave and a series of 25-ns 314.4-GHz pulses, respectively. In the experiments, the Si wafer was driven by a 55.7-mJ green-laser pulse (DPS-532-BS-D-50mJ, Changchun New Industries Optoelectronics Tech. Co., Ltd., CN) with a central wavelength of 532.263 nm. The 314.4-GHz waves were incident on the Si wafer at Brewster's angle (about 73.7 degrees).

The normalized temporal profile of the green-laser pulse is presented in Normalized_pump_laser_pulse.rtf. The normalized reflectance from the measurement with the continuous 314.4-GHz wave is presented in Normalized_Reflectance_cw_experiment.rtf. 

The reflectance values from the measurement with 25-ns 314.4-GHz pulses are presented in Mean_Reflectance_pulse_experiment.rtf. Each reflectance value was taken as the total energy in the reflected pulse normalized with respect to the total energy in the input pulse. The averaged reflectance values were recorded as a function of the time at the rising edge of each 25-ns 314.4-GHz pulse. The temporal profile of two 314.4-GHz pulses are presented in Normalized_sub_THz_pulse_1.rtf and Normalized_sub_THz_pulse_2.rtf, respectively.

The effective-lifetime data were collected by Anup Yadav and Sophie L. Pain from the School of Engineering, University of Warwick, Coventry, CV4 7AL, UK.

The raw data from the reflectance measurements were collected by Antonín Sojka and processed by Qile Wu in University of California, Santa Barbara, California 93106, USA.