Control of photocurrent in semiconductors through femtosecond pulses

Abstract

Phase-coherent control of photocurrent magnitude and directionality in semiconductors using linearly chirped pulses is proposed and analysed. Measurable photocurrents can be generated for the pulsewidth shorter than the dephasing time of the excited carriers.

Charge Coupled Devices as Particle Detectors

“…The specialty literature involves also a rather large number of nanoimpurities and nanodefect types that can affect the quality of the silicon crystalline lattice. The study of these nanoimpurities and defects began even before (see, e.g., [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]) the invention (in 1969) of the charge coupled devices, "culminated" with the elaboration of the main experimental methods used to identify and characterize them [25][26][27][28][29][30][31][32][33][34][35][36][37][38], and continues nowadays (see, e.g., [39][40][41]). The CCDs image sensors are extremely sensitive to contamination by heavy metals, which form Shockley-Reed-Hall deep-level traps that generate dark current in the imager region of the silicon device [28,32].…”

“…This dark current from defects scattered among the imager pixels represents a source of pattern noise and may cause the pixels and even the imager to be defective. The deep-level transient spectroscopy (DLTS [25][26][27]) and the dark current spectroscopy (DCS, [28][29][30][31][32][33][34][35][36][37][38]) methods allow the study of these deep-level traps in silicon at concentrations even of only 10 7 nanotraps/cm 3 .…”