Abstract: An electrochemical cell includes: a positive current collector in which an injection part, an ejection part and a passage are defined, where air including an oxygen is injected through the injection part, an exhaust gas is ejected though the ejection part ejecting, and the passage defines a single path which connects the injection part and the ejection part; and a unit cell disposed to be adjacent to the positive current collector. The unit cell includes a positive electrode layer, an active material of which is the oxygen gas, a negative electrode metal layer disposed on an opposite to the positive current collector with respect to the positive electrode layer, and an electrolyte membrane interposed between the positive electrode layer and the negative electrode metal layer.

Abstract: A High electron mobility transistor (HEMT) includes a source electrode, a gate electrode, a drain electrode, a channel forming layer in which a two-dimensional electron gas (2DEG) channel is induced, and a channel supplying layer for inducing the 2DEG channel in the channel forming layer. The source electrode and the drain electrode are located on the channel supplying layer. A channel increase layer is between the channel supplying layer and the source and drain electrodes. A thickness of the channel supplying layer is less than about 15 nm.

Abstract: An electrochemical cell includes: a positive current collector in which an injection part, an ejection part and a passage are defined, where air including an oxygen is injected through the injection part, an exhaust gas is ejected though the ejection part ejecting, and the passage defines a single path which connects the injection part and the ejection part; and a unit cell disposed to be adjacent to the positive current collector. The unit cell includes a positive electrode layer, an active material of which is the oxygen gas, a negative electrode metal layer disposed on an opposite to the positive current collector with respect to the positive electrode layer, and an electrolyte membrane interposed between the positive electrode layer and the negative electrode metal layer.

Abstract: High electron mobility transistors (HEMT) exhibiting dual depletion and methods of manufacturing the same. The HEMT includes a source electrode, a gate electrode and a drain electrode disposed on a plurality of semiconductor layers having different polarities. A dual depletion region exists between the source electrode and the drain electrode. The plurality of semiconductor layers includes an upper material layer, an intermediate material layer and a lower material layer, and a polarity of the intermediate material layer is different from polarities of the upper material layer and the lower material layer.

Abstract: According to example embodiments, a high electron mobility transistor (HEMT) includes: stack including a buffer layer, a channel layer containing a two dimensional electron gas (2DEG) channel, and a channel supply layer sequentially stacked on each other, the stack defining a first hole and a second hole that are spaced apart from each other. A first electrode, a second electrode, and third electrode are spaced apart from each other along a first surface of the channel supply layer. A first pad is on the buffer layer and extends through the first hole of the stack to the first electrode. A second pad is on the buffer layer and extends through the second hole of the stack to the second electrode. A third pad is under the stack and electrically connected to the third electrode.

Abstract: According to example embodiments, a high electron mobility transistor (HEMT) includes a channel supply layer that induces a two-dimensional electron gas (2DEG) in a channel layer, a source electrode and a drain electrode that are at sides of the channel supply layer, a depletion-forming layer that is on the channel supply layer and contacts the source electrode, a gate insulating layer on the depletion-forming layer, and a gate electrode on the gate insulating layer. The depletion-forming layer forms a depletion region in the 2DEG.

Abstract: According to example embodiments a transistor includes a channel layer on a substrate, a first channel supply layer on the channel, a depletion layer, a second channel supply layer, source and drain electrodes on the first channel supply layer, and a gate electrode on the depletion layer. The channel includes a 2DEG channel configured to generate a two-dimensional electron gas and a depletion area. The first channel supply layer corresponds to the 2DEG channel and defines an opening that exposes the depletion area. The depletion layer is on the depletion area of the channel layer. The second channel supply layer is between the depletion layer and the depletion area.

Abstract: According to example embodiments, a method for controlling a gate voltage applied to a gate electrode of a high electron mobility transistor (HEMT) may include measuring a voltage between a drain electrode and a source electrode of the HEMT, and adjusting a level of the gate voltage applied to the gate electrode of the HEMT according to the measured voltage. The level of the gate electrode may be adjusted if the voltage between the drain electrode and the source electrode is different than a set value.

Abstract: Field effect semiconductor devices and methods of manufacturing the same are provided, the field effect semiconductor devices include a second semiconductor layer on a first surface of a first semiconductor layer, a first and a second third semiconductor layer respectively on two sides of the second semiconductor layer, a source and a drain respectively on the first and second third semiconductor layer, and a gate electrode on a second surface of the first semiconductor layer.

Abstract: High electron mobility transistors (HEMTs) including lightly doped drain (LDD) regions and methods of manufacturing the same. A HEMT includes a source, a drain, a gate, a channel supplying layer for forming at least a 2-dimensional electron gas (2DEG) channel, and a channel formation layer in which at least the 2DEG channel is formed. The channel supplying layer includes a plurality of semiconductor layers having different polarizabilities. A portion of the channel supplying layer is recessed. One of the plurality of semiconductor layers, which is positioned below an uppermost layer is an etching buffer layer, as well as a channel supplying layer.

Abstract: A nitride-based semiconductor diode includes a substrate, a first semiconductor layer disposed on the substrate, and a second semiconductor layer disposed on the first semiconductor layer. The first and second semiconductor layers include a nitride-based semiconductor. A first portion of the second semiconductor layer may have a thickness thinner than a second portion of the second semiconductor layer. The diode may further include an insulating layer disposed on the second semiconductor layer, a first electrode covering the first portion of the second semiconductor layer and forming an ohmic contact with the first semiconductor layer and the second semiconductor layer, and a second electrode separated from the first electrode, the second electrode forming an ohmic contact with the first semiconductor layer and the second semiconductor layer.

Abstract: An electronic device may include a first transistor having a normally-on characteristic; a second transistor connected to the first transistor and having a normally-off characteristic; a constant voltage application unit configured to apply a constant voltage to a gate of the first transistor; and a switching unit configured to apply a switching signal to the second transistor. The first transistor may be a high electron mobility transistor (HEMT). The second transistor may be a field-effect transistor (FET). The constant voltage application unit may include a diode connected to the gate of the first transistor; and a constant current source connected to the diode.

Abstract: The methods may include forming a first material layer on a substrate, increasing electric resistance of the first material layer, and forming a source pattern and a drain pattern, which are spaced apart from each other, on the first material layer, a band gap of the source and drain patterns greater than a band gap of a first material layer.

Abstract: Provided are a high electron mobility transistor (HEMT) and a method of manufacturing the HEMT. The HEMT includes: a channel layer comprising a first semiconductor material; a channel supply layer comprising a second semiconductor material and generating two-dimensional electron gas (2DEG) in the channel layer; a source electrode and a drain electrode separated from each other in the channel supply layer; at least one depletion forming unit that is formed on the channel supply layer and forms a depletion region in the 2DEG; at least one gate electrode that is formed on the at least one depletion forming unit; at least one bridge that connects the at least one depletion forming unit and the source electrode; and a contact portion that extends from the at least one bridge under the source electrode.

Abstract: According to example embodiments, a high electron mobility transistor (HEMT) includes a channel layer; a channel supply layer on the channel layer; a source electrode and a drain electrode spaced apart from each other on one of the channel layer and the channel supply layer; a gate electrode on a part of the channel supply layer between the source electrode and the drain electrode; a first depletion-forming layer between the gate electrode and the channel supply layer; and a at least one second depletion-forming layer on the channel supply layer between the gate electrode and the drain electrode. The at least one second depletion-forming layer is electrically connected to the source electrode.

Abstract: High electron mobility transistors (HEMTs) including a cavity below a drain and methods of manufacturing HEMTS including removing a portion of a substrate below a drain.

Abstract: A high electron mobility transistor (HEMT) according to example embodiments includes a channel layer, a channel supply layer on the channel layer, a source electrode and a drain electrode on at least one of the channel layer and the channel supply layer, a gate electrode between the source electrode and the drain electrode, and a Schottky electrode forming a Schottky contact with the channel supply layer. An upper surface of the channel supply layer may define a Schottky electrode accommodation unit. At least part of the Schottky electrode may be in the Schottky electrode accommodation unit. The Schottky electrode is electrically connected to the source electrode.

Abstract: A power switching device includes a channel forming layer on a substrate which includes a 2-dimensional electron gas (2DEG), and a channel supply layer which corresponds to the 2DEG at the channel forming layer. A cathode is coupled to a first end of the channel supply layer and an anode is coupled to a second end of the channel supply layer. The channel forming layer further includes a plurality of depletion areas arranged in a pattern, and portions of the channel forming layer between the plurality of depletion areas are non-depletion areas.

Abstract: A semiconductor device includes a first compound semiconductor layer on a substrate, first through third electrodes spaced apart from each other on the first compound semiconductor layer, a second compound semiconductor layer on the first compound semiconductor layer between the first through third electrodes, a third compound semiconductor layer on the second compound semiconductor layer between the first and second electrodes, a first gate electrode on the third compound semiconductor layer, a fourth compound semiconductor layer having a smaller thickness than the third compound semiconductor layer on a portion of the second compound semiconductor layer between the second and third electrodes, and a second gate electrode on the fourth compound semiconductor layer. The first compound semiconductor layer between the second and third electrodes includes a 2-dimensional electron gas (2DEG) and the third compound semiconductor layer includes a 2-dimensional hole gas (2DHG).

Abstract: Provided are high electron mobility transistors (HEMTs), methods of manufacturing the HEMTs, and electronic devices including the HEMTs. An HEMT may include an impurity containing layer, a partial region of which is selectively activated. The activated region of the impurity containing layer may be used as a depletion forming element. Non-activated regions may be disposed at opposite side of the activated region in the impurity containing layer. A hydrogen content of the activated region may be lower than the hydrogen content of the non-activated region. In another example embodiment, an HEMT may include a depletion forming element that includes a plurality of regions, and properties (e.g., doping concentrations) of the plurality of regions may be changed in a horizontal direction.