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Polarization effect on time‐of‐flight measurements performed on a CVD diamond single crystal
Author(s) -
Valentin Audrey,
Tardieu André,
Mille Vianney,
Tallaire Alexandre,
Achard Jocelyn,
Gicquel Alix
Publication year - 2015
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201532205
Subject(s) - diamond , electron , electric field , time of flight , materials science , polarization (electrochemistry) , biasing , single crystal , condensed matter physics , atomic physics , optics , chemistry , voltage , nuclear magnetic resonance , physics , quantum mechanics , composite material
Time‐of‐flight experiments have been performed on a freestanding CVD diamond sample with Ti–Au contacts. Electron–hole pairs are generated with alpha rays from an 241 Am source. A low‐field mobility of 2972 cm 2 /Vs and a saturation velocity of 12.3 × 10 6 cm/s have been extracted from the hole current pulses. However, the obtained electrons pulse shapes do not allow a clear determination of the mobility. The electrons appear to be slowed down by space‐charges located near the contacts. This clear polarization effect is attributed to negative charges trapped at the metal/diamond interface. Its influence has been investigated by comparing the current pulses obtained when applying a negative or positive bias. This bias influences the electric field inside the sample. Two competitive effects can be identified: a bulk effect and a contact effect. Time‐of‐flight can thus be used to identify the presence of defects in diamond crystals for electronic applications.