UVC LED The physical mechanism of chip light efficiency attenuation

UVC LED Chips as an efficient tool, Environmentally friendly UV light source, In sterilization and disinfection, water purification, The medical and other fields have broad application prospects. however, The problem of light attenuation has always been a key bottleneck restricting its development and application. in-depth understanding UVC LED The physical mechanism of chip light efficiency attenuation, To improve its performance, Extending the service life is of great significance.

UVC LED The core material of the chip is a wide bandgap semiconductor, Such as aluminum gallium nitride (AlGaN) . The changes in the characteristics of the material itself are one of the important reasons for the attenuation of light efficiency.

During the long-term work process, AlGaN Materials will undergo defect evolution. Vacancies are inevitably generated during the process of crystal growth, Native defects such as dislocations, Under the influence of current injection and temperature rise, These defects will migrate, Aggregation and proliferation. The movement of vacancies may form new composite centers, The proliferation of dislocations will lead to an increase in the probability of non radiative recombination of charge carriers, Reduce the number of charge carriers originally used for luminescence, Thereby reducing the light efficiency.

Besides, The uneven composition of materials can also exacerbate the attenuation of light efficiency. AlGaN Aluminum in the material (Al) Uneven distribution of components can lead to fluctuations in the bandgap width, Form local potential wells or barriers. Carriers will be captured by these local potential fields during transport, Increased the possibility of non radiative recombination, Leading to a decrease in light efficiency. and, Uneven composition can also affect the optical properties of materials, Drift the emission wavelength, Further reduce the luminous efficiency of the device.

UVC LED Chips typically adopt a multi quantum well structure, Quantum well is a key region for achieving efficient luminescence, The quality of heterojunction interfaces has a significant impact on the performance of quantum wells.

Lattice mismatch at heterojunction interfaces can generate stress, During the long-term work process, The release of stress can lead to defects at the interface. These interface defects will become recombination centers for charge carriers, Causing non radiative recombination of charge carriers before they reach the quantum well, Reduced the luminescence efficiency of quantum wells. simultaneously, Interface defects can also affect the transport of charge carriers between heterojunctions, Increased the transport resistance of charge carriers, Further intensify the attenuation of light efficiency.

The degradation of quantum well structures is also an important factor leading to the attenuation of light efficiency. Under the influence of current and temperature, The width and depth of quantum wells will vary. The increase in quantum well width will weaken the confinement effect of charge carriers, Enable more charge carriers to diffuse outside the quantum well and undergo non radiative recombination; The reduction of quantum well depth will lower the probability of radiative recombination of charge carriers, This leads to a decrease in light efficiency.

The electrode is UVC LED Key components for current injection in chips, The degradation of its performance will directly affect the light efficiency of the chip.

During the long-term work process, Electrode materials will undergo oxidation, Migration and diffusion. Oxidation of electrodes can lead to an increase in their resistance, Increased difficulty in current injection, Reduce the operating current of the chip, Thereby reducing the optical output power. The migration and diffusion of electrode materials may also lead to changes in electrode shape, Disrupting the contact between electrodes and semiconductor materials, Further affecting the uniform injection of current.

The degradation of Ohmic contact is also an important cause of light efficiency attenuation. Ohmic contact is the key to achieving low resistance contact between electrodes and semiconductor materials, The quality directly affects the injection efficiency of the current. During the long-term work process, The Ohmic contact area will undergo thermal aging and chemical changes, Causing an increase in contact resistance. An increase in contact resistance will generate more Joule heating during the injection process of the current, Not only will it reduce the luminous efficiency of the chip, It may also cause an increase in chip temperature, Accelerate the degradation of other components.

UVC LED The working environment of chips also has a significant impact on their light efficiency attenuation.

Temperature has an impact UVC LED One of the key factors affecting chip performance. Chips generate a large amount of heat during operation, If there is poor heat dissipation, Will cause an increase in chip temperature. High temperature will exacerbate the evolution of defects in materials, Degradation of quantum well structure and degradation rate of electrode and Ohmic contact. simultaneously, High temperatures can also increase the probability of non radiative recombination of charge carriers, Reduce luminous efficiency.

Humidity and corrosive gases can also affect UVC LED The performance of the chip is adversely affected. An environment with high humidity can cause oxidation and corrosion on the surface of the chip, Destroy the surface structure of the chip, Affects the extraction efficiency of light. Corrosive gases will undergo chemical reactions with chip materials, Causing material performance degradation, Thereby affecting the light efficiency of the chip.

In summary, UVC LED The attenuation of chip light efficiency is a complex physical process, Involving changes in material properties, Heterojunction interface and quantum well structure degradation, Degradation of electrode Ohmic contact and external environmental factors, among other aspects. In depth study of these physical mechanisms, For developing high-performance, Long lived UVC LED Chips have important guiding significance. future, By optimizing the material growth process, Measures such as improving device structure design and enhancing packaging and heat dissipation performance, Expected to effectively suppress UVC LED Light efficiency attenuation of chips, Promote its widespread application in more fields.