My field of interest is a solid state physics; mainly, optical and electrical properties of III-V semiconductors.
I investigate luminescence, photosensitivity and conductivity of these materials. This materials can be use to produce UV AlGaInN detector. In my lab in Institute of Experimental Physics I have built a set-up for measurements of low currents. This setup is well prepared for measurements of photo-current, thermally stimulated current TSC, and photo-induced current-transient spectroscopy (PICTS). Thanks to collaboration with Max Planck Institute in Stuttgart, I can measure time-resolve photoluminescence spectra using a streak-camera.
UV detector containing GaInN QW with AlGaN barriers
(A) Photograph of the sample. (B) Map of intensity of the GaInN QW peak. (C) Map of wavelength of the GaInN QW peak.
Equipment for measurements of time-resolved photoluminescence
with a streak camera.
In this experimental technique a laser pulse excites a sample in a cryostat. The photoluminescence signal from the sample is first dispersed in the mono- chromator (spectral-resolution) and then fed into a streak camera for temporal resolution. (In the streak camera the light beam is converted to electron beam, which goes through a sweeping device where it is swept like in oscilloscope.) Finally the obtained signal is spectrally- and time- resolved. The advantage of this method is the simultaneous recording of many transients at the same time, which gives a possibility of reliable comparison of various processes.
 Spectrally and temporally resolved photoluminescence of a GaN/AlGaN sample. |
 InAs/GaAs structur with quantum dots. |
III-V semiconductors
III-V semiconductors are compounds made of elements from third and fifth groups of periodic table of elements. For example, gallium (Ga) from the third group and arsenic (As) from the fifth group form gallium arsenide (GaAs). Well known semiconductor germanium (Ge) is made of atoms from the forth group. If, in Ge crystal, somebody replaces one Ge atom by Ga and next Ge atom by As, will obtain GaAs crystal. Most of III-V and II-VI semiconductors crystallize in zinc-blend (cubic ZnS) or wurtzite (hexagonal ZnS) structures. Typical example of cubic crystal is gallium arsenide, GaAs, lattice (see below). Typical example of hexagonal structure is gallium nitride, GaN (see below).
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