Imprint electric field controlled electronic transport in TlGaSe2 crystals

Abstract

The effect of built–in electric field onto the dc electrical conductivity, photoconductivity, and electrical switching phenomenon were investigated in TlGaSe2 layered semiconductor within the temperature range of 77–300 K. We have used different types of electrodes for different TlGaSe2 samples in both parallel and perpendicular directions to the plane of layers. The effect of electric field was investigated by cooling the samples from the room temperature under the electric field and then removing it at ∼80 K. After the procedure, it was found that a built-in internal electric field which strongly affects transport properties appears in TlGaSe2 crystals. Substantial increasing of both dark currents and photo-conductivities were observed predominantly at low temperatures, where hopping was the main conductivity mechanism. The anomalous decrease of the activation energy in the low temperature region and the switching effect are also the main experimental findings of the present work. Such behavior can be understood by assuming that the built-in electric field greatly increases the contribution of the hopping conductivity at low temperatures. Obtained results are discussed on the basis of the models widely used for disordered semiconductors. It was shown that TlGaSe2 crystal demonstrates the peculiar behavior that is typical to such type of semiconductors.

Enhancing the photoresponse of a TlGaSe2semiconductor for ultraviolet detection applications

“…As was shown in our previous investigations [20], the built-in electric field substantially increases the conductivity within the volume of the crystals as in the case of disordered semiconductors. We have shown that TlGaSe 2 behaves in many respects as a disordered semiconductor [20,21].…”

“…As was shown in our previous investigations [20], the built-in electric field substantially increases the conductivity within the volume of the crystals as in the case of disordered semiconductors. We have shown that TlGaSe 2 behaves in many respects as a disordered semiconductor [20,21]. So, the main experimental findings of the present work are based on the model which considers the TlGaSe 2 as a disordered semiconductor with a native thin insulating layer on its surface.…”

Эффект модификации вклада термоэмиссии локализованных зарядов в релаксацию фотоотклика монокристалла TlGaSe-=SUB=-2-=/SUB=-

“…Таким образом, можно заключить, что электрическая неоднородность кристалла, сформированная в результате перестройки доменной структуры (поляризацией образца под действием внешнего поля в низкотемпературной сегнетофазе), сохраняется и в высокотемпературной области параэлектрического состояния кристалла, где эти неоднородности можно сопоставить исключительно с пространственно неоднородным заполнением ЦЛЗ. Эти данные хорошо согласуются с результатами ряда исследований различного рода эффектов памяти [5,[19][20][21][22][23][24][25].…”

Enhanced excitonic photoconductivity due to built-in internal electric field in TlGaSe2 layered semiconductor

“…In a series of recent studies, [5][6][7] we have discovered the presence of a built-in internal electric field in TlGaSe 2 single crystals, which significantly changes the electronic transport properties of this material. The built-in internal electric field is pumped into the TlGaSe 2 by cooling the crystal from room temperature down to 77 K under the existence of an external electric field.…”

“…It has been found that after the termination of the pretreatment in the electric field, a built-in internal electric field persists for a relatively long duration, even at temperatures well above the temperatures of phase transitions. 5 This built-in internal electric field is one of the most interesting yet not well understood phenomena in TlGaSe 2 semiconductor.…”