Multiple quantum well structure for photoelectric device

Abstract

The invention discloses a multiple quantum well structure for a photoelectric device, which comprises n quantum well structures overlapped sequentially. The photoelectric device comprises an N-type semiconductor layer and a P-type semiconductor layer, and is characterized in that the thickness of the barrier layer close to the N-type semiconductor layer is larger than the thickness of the barrier layer close to the P-type semiconductor layer; and n is an integer which is larger than 2 and less than 20. The invention can improve the internal quantum efficiency, and because the barrier layer close to the N layer is wider, the invention can compel holes to move near to the N layer, thereby increasing the number of luminous quantum wells and improving the luminous efficiency of the quantum wells and the brightness. The invention can increase the backward voltage and improve the antistatic property, and because the barrier layer close to the N layer is thicker than the barrier layer close to the P layer, a PN junction is widened when the backward voltage is applied.

Description

technical field [0001] The invention relates to a structure used in a photoelectric device, in particular to a multi-quantum well structure used in a photoelectric device. Background technique [0002] Light-emitting diodes (LEDs) semiconductor light-emitting diodes use electrons and holes to travel from n-type doped regions and p-type doped regions to the active region for recombination to generate radiative transitions and emit light. However, first of all, because the electron concentration of the n-GaN layer is generally several orders of magnitude higher than the hole concentration in the p-GaN layer, this will cause the light-emitting interface to be close to the p-layer. When the light-emitting interface is close to the p-layer, only 1 -The radiative transition of the two quantum wells contributes to the luminescence, and it is difficult to make a big breakthrough in brightness. At the same time, because the luminous interface is close to the p-layer, the quantum well...

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Problems solved by technology

However, first of all, because the electron concentration of the n-GaN layer is generally several orders of magnitude higher than the hole concentration in the p-GaN layer, this will cause the light-emitting interface to be close to the p-layer. When the light-emitting interface is close to the p-layer, only 1 -The radiative transition of the two quantum wells contributes to the luminescence, and it is difficult to make a big breakthrough in brightness. At the same time, because the luminous interface is close to the p-layer, the quantum well farther away from the p-layer has a non-radiative transition due to the existence of the quenching center. The probability of increasing the Joule heat will increase, which will make it difficult to effectively improve the life of the device; secondly, due to the large gap between the concentration and mobility of holes and electrons, electrons are easier to transport to deeper layers than holes The quantum well active area of ​​the quantum well, and the excess electrons will eventually form an ineffective current because they cannot recombine with the holes, thereby reducing the current injection efficiency of the device; finally, due to the polarization effect in the gallium nitride-based light-emitting diode, the quantum well There is a strong polarized electric field in the medium, and the electrons and holes are separated by space, resulting in a significant reduction in the probability of radiative recombination. Therefore, people usually use a narrower quantum well structure to increase the radiative recombination probability of electron holes, but the narrower quantum well structure It will lead to lower capture probability of electrons and holes, reducing the efficiency of LED current injection

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