Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 10 of 10 for “"band tail"”.
-
Photoluminescence study of Cu(In,Ga)Se2 and Cu2ZnSnSe4 used for thin film solar cells
… achieved at about 30% Ga, whereas the optimal band gap requires much higher Ga content (around 50%). Also for the first time ever we examined the effects of 4 keV Ar+ irradiation on optical properties of Cu2ZnSnSe4 (CZTSe) thin films. Photoluminescence (PL) measurements were performed on …
-
Steady state and transient photoconductivity in n-type amorphous silicon
… determination of the distribution of conduction band tail (CBT) states, and hence comparison of the quality of the two materials. A broad exponential tail of high state density was found for the As-doped material while the CBT in the P-doped material was found to be characterised by a shallow …
-
Thermally stimulated currents and photoconductivity in microcrystalline silicon
… measurements and simulations demonstrate in detail two different retrapping regimes (strong and weak). A combined experiment - simulation approach allows to extract the density-of-states profile and to deduce trap parameters. For ñc-Si:H samples, the conduction band tail parameters vary between …
-
Optical characterization of copper indium gallium diselenide thin films
… and their relation to grain boundaries and band edge fluctuations, which limit device performance. This study used photoluminescence (PL) spectroscopy, photoluminescence excitation (PLE) spectroscopy, and cathodoluminescence (CL) to study radiative emissions from a variety of Cu-poor CIGS …
-
Time and frequency resolved photoconductivity studies on amorphous semiconductors
… gap. The DOS consists of an 0.03 eV exponential band-tail, and a bump of 4.4x10<sup>16</sup>cm<sup>-3</sup> states at 0.65eV below E<sub>c</sub>, attributed to dangling bonds. The method detects the bump despite there being no related emission feature in the TPC decay. The accuracy of the …
-
Ionizing Radiation Resistance of Random Hole Optical Fiber for Nuclear Instrumentation and Control Applications
… fibers could be attributed to the OH absorption band tail. However, the existence of other mechanisms responsible for RIA is also postulated. Some of these mechanisms include bulk and surface defects which are related to the fabrication process and the influence of the gases confined within the …
-
Electronic transport properties of thin films of amorphous silicon
… are interpreted in terms of localised conduction band tail states extending to approximately 0.2 eV below the conduction band mobility edge, and a discrete set of localised states situated at 0.4 eV below the conduction band mobility edge. It is suggested that the extent of the tail states and the …
-
Carrier mobility of downscaled amorphous semiconductors exemplified by hydrogenated amorphous silicon
… The theory focusses on the universal band tails found in the density of states (DOS) of amorphous semiconductors, which affects charge transport. Using hydrogenated amorphous silicon (a-Si:H) as an example, excess valence band and conduction band electrons stemming from the distortion …
-
OPTICAL CHARACTERIZATION OF WIDE ENERGY AGP GROUP III-NITRIDE SEMICONDUCTORS
… findings of the optical characterization of wide-band gap group III nitrides. Several optical spectroscopic techniques were applied to GaN and related materials grown by metalorganic chemical vapor deposition (MOCVD). Variable-temperature photoluminescence (PL) spectra were measured for a series …
-
Characterization of type-II GaSb quantum rings in GaAs solar cells
… visible out towards 1.4 µm giving a near optimum band gap for concentrator solar cell applications. Also, in type II band alignment the electrons are weakly localized and the built in electric field drifts the electrons across the depletion region easily. However, the introduction of GaSb QRs in …