I will review our combined local-probe and transport measurements on three types of semiconductor chalcogenide systems. Starting with Cu2S nanocrystals, I will present a new method for achieving p-type doping, by which Cu vacancies are formed upon annealing at moderate temperatures, yielding free holes. Consequently, the conductance of Cu2S nanocrystals arrays increases by 4-6 orders of magnitude. This method enable patterned doping by applying focused laser illuminations. Next, I will discuss the origin of the surprisingly high conversion efficiency of polycrystalline Cu(In,Ga)Se solar-cells, focusing on the role of grain-boundaries. Local-probe scanning tunneling spectroscopy (STS) and conductive-probe atomic force microscopy measurements provide evidence for significant band-bending at grain-boundaries, assisting the collection efficiency of photo-generated minority (electron) charges, and reduced deep-level density of states, reducing the recombination rate. Finally, STS measurements on CdSe nanoplatelets will be presented, providing first evidence for a unique two-dimensional behavior and quantum-confinement associated with their thickness only.
|Original language||American English|
|Title of host publication||2016 Compound Semiconductor Week, CSW 2016 - Includes 28th International Conference on Indium Phosphide and Related Materials, IPRM and 43rd International Symposium on Compound Semiconductors, ISCS 2016|
|Publisher||Institute of Electrical and Electronics Engineers Inc.|
|State||Published - 1 Aug 2016|
|Event||2016 Compound Semiconductor Week, CSW 2016 - Toyama, Japan|
Duration: 26 Jun 2016 → 30 Jun 2016
|Name||2016 Compound Semiconductor Week, CSW 2016 - Includes 28th International Conference on Indium Phosphide and Related Materials, IPRM and 43rd International Symposium on Compound Semiconductors, ISCS 2016|
|Conference||2016 Compound Semiconductor Week, CSW 2016|
|Period||26/06/16 → 30/06/16|
Bibliographical notePublisher Copyright:
© 2016 IEEE.
- CIGSe solar-cells
- atomic force microscopy
- scanning tunneling spectrsocopy