Gallium Phosphide (GaP) III-V Semiconductor Wafers
Gallium Phosphide Optical Clarity
The most significant property of gallium phosphide that distinguishes it 
from other materials is its great optical clarity. When viewed through a scope, its wavy thickness shows bright bands in the spectrum. As seen from the figure above, the internal lines of single crystals are easily seen. In addition, the brilliance of the bands is enhanced if the device is viewed through an ultraviolet (UV) light source.
UniversityWafer, Inc. gallium phosphide wafers work great in solar cells and energy conversion, and can increase efficiency and produce more clean energy for our planet.
Get Your GaP Wafer Quote FAST!
Gallium Phosphide (GaP) for Terahertz (THz) Radiation Generation
A researcher asked:
We are looking for a GaP <110> sample for THz generation. The ideal thickness is 0.5mm or 1mm.
The wafer should be polished on both sides and, it possible, AR-coated at 1030nm.
Solution:
GaP 25mm x 25mm Undoped (110)+/-0.5 deg 1,000 micron Double Side Polished Epi Ready
Other diameters available. Researcher was looking for least expenseive.
UniversityWafer’s Gallium Phosphide Substrates Helps Develop Patterned Surfaces at Nanometer Scale
UniversityWafer provided researchers from Lawrence Berkeley National Laboratory with single crystalline (100) GaP wafers. These wafers were p-type doped with zinc. Their resistivity was 0.3 Ω cm with an Single Side Polished (SSP) epi-ready finish. This process was used to establish a new way to absorb light and produce clean, environmentally friendly energy.
What are the Benefits of Using Gallium Phosphide (GaP) Wafers?
Gallium phosphide (GaP) is a non-toxic and transparent semiconductor that is used in many telecommunications devices. It is said to have one of the best all-over performance. Gallium Phosphide is manufactured through a process called ionic diffusion. The material exhibits an extended band of hardness (between 0.73 and 0.75 micrometer) and superior electrical characteristic. One of its most important physical characteristics is its high correlation to gallium nitride, which is widely used in photovoltaic and optoelectronic applications.
The ganthanic compound has the look of tiny black dots. The crystals have a bluish color, which can be attributed to high solvation of the gallium indium phosphide in the silicon substrate. Undoped single crystal devices also exhibit clear red wafers, while highly doped single crystal devices seem black, because of free-Carrier absorption.
Gallium phosphide (GaP) exhibits some unique physical properties that make it ideal for use in photovoltaic systems, electronics, and energy transfer. It has high solubility, which makes it soluble in water. Solubility gives it the ability to diffuse into other liquids with low-molecular weight. This property makes it possible to build wafers from small solids such as silica and quartz. In addition, Undoped Silicon Wafers (Si) is insoluble in water and separates readily between Si and water. Single-crystal devices based on gallium phosphide (Ig) are capable of producing electrical power, whereas bulk Icos based on Pd are unable to do so.
Gallium phosphide can be formed in various ways. It can be formed from gallium nitrate (CHN) or gallium phosphate (DIP), which is the common semiconductor wafer substrate used in industries. Gallium phosphate is inexpensive and commonly found in many industries. However, its thermal stability is poor. Moreover, its high vapor transmission rate reduces its cost.
In contrast, gallium phosphide is a semiconductor compound that is formed directly from Gallium Nitride (GaN). Its optical clarity is superior to that of the former. Hence, it exhibits superior performance in applications requiring short-wave transmission and energy conversion. Moreover, gallium phosphide exhibits good electrical and optical properties, which are unique in the context of semiconductor materials. It is also used in medical devices because of its anti-toxicity property.
Silicon carbide is a white crystalline powder and was initially developed as an alternative to gallium phosphide due to its high purity. Silicon carbide has low density, which makes it a suitable material for dosing equipment. Silicon carbide can be used as a substitute for Pd as it yields higher purity. The electrical and optical properties of silicon carbide make it a good semiconductor compound for optoelectronic applications.
Tungsten trioxide is a popular choice for coloring semiconductors due to its colorless, smooth, and highly conductive property. However, tungsten trioxide's high melting point makes it a poor choice for use in electronics as it can easily get bubbled. A novel method called dopant dissolution is gaining popularity for preparing semiconductor materials such as gallium phosphide using common dietary products. Dopant dissolution uses a solution of potassium in a doped mixture of tungsten trioxide crystals.
Gallium phosphide, Silicon Carbide (SiC), Indium Phosphide (InP) wafer thicknesses, and doping equipment are important components in desktop testing systems. These testing supplies help in quality assurance, yield testing, and stability testing of semiconducting systems. Moreover, these testing supply products have low cost of manufacturing, easy handling, flexibility, safety, durability, and value for money. Overall, the benefits of using gallium phosphide, silicon carbide, indium phosphide wafer thicknesses, and doping equipments are considerable.
What Are Gallium Phosphide Wafers Used For?
Gallium phosphide wafers are widely used in semiconductor devices. The material's transparent nature makes it an ideal choice for the fabrication of LEDs and other high-efficiency devices. However, this material is not free from defects. As a result, it is often used in LEDs at relatively low costs. Nevertheless, its optical properties are also limited, which makes it less suitable for high-end applications.
Gallium phosphide wafers are made using a single-crystal GaP. These are grown using a LEC method, using 6N high-purity materials. This semiconductor material is widely used in displays and red LEDs. Because of its excellent quality and high-performance properties, this material is commonly used in display elements and LCD backlights.
Gallium phosphide is a compound semiconductor with a broad indirect band gap. Its crystal structure is similar to silicon and the lattice constant is 0.545 nm. It has high solubility, allowing electrons to diffuse into low-molecular-weight liquids, and is insoluble in water. Due to its favorable properties, gallium phosphide is widely used in optical systems.
UniversityWafers provides single-crystal GaP gallium phosphide wafer, grown using a six-nanometer process. This material is very well-made and is used as a yellow and red LED. In addition, it is also widely used in LCD display elements and the backlight of LCDs. Its good quality makes it a great choice for display elements.
Gallium phosphide is a polycrystalline compound semiconductor that has a wide range of applications. It is a white-gray material that has a small indirect band gap of 2.26 eV. Unlike silicon, gallium phosphide has a high refractive index. It is a good choice for display elements and LCD backlights.
Gallium phosphide is a nonlinear compound semiconductor with a broad range of applications. Its indirect bandgap is 2.26 eV, making it one of the most accessible semiconductor materials. The material is transparent to visible light and long-infrared radiation. Its high-resolution transparency makes it an ideal choice for medical devices. If you're looking for a semiconductor, this is an excellent choice for your project.
Gallium phosphide is a compound semiconductor. Its indirect band gap is 2.26 eV (300K). Its n-type and p-type semiconductors are characterized by a narrower band gap. Consequently, these two materials are very useful in a wide variety of applications. Its p-type counterparts have an increased ability to absorb ultraviolet light.
Gallium Phosphide Light Emitting Diodes
In addition to being useful for LEDs, gallium phosphide wafer is also a popular material for solar cells. These devices are used in LED manufacturing and are widely available in the market. This material is available in several different types, and its benefits include the ability to produce clean energy. The compound semiconductors can be fabricated with ease. If you're interested in making your own LEDs, gallium phosphides are a good choice.
The use of gallium phosphide wafer is widespread. It can be used as an LED, which is a popular type of LED. Its high optical property allows it to be used in a number of different electronic devices. The high optical quality of these components means they're highly versatile. If you're looking for a semiconductor that can perform in many applications, gallium phosphide is an excellent choice.
As a result, gallium phosphide wafer is an important component of many desktop testing systems. Its n-type and p-type semiconductors are used for laser diodes and other devices. The material's low density makes it suitable for dosing equipment. Its high optical and electrical properties make it a perfect choice for optoelectronic applications.
Gallium Phosphide Semiconductor
Gallium phosphide is an extremely versatile semiconductor. It is an excellent choice for use in solar cells and in solar panels. Its high optical properties make it an ideal material for many applications. The material's low resistance and high electrical conductivity makes it the perfect semiconductor for electronic and photovoltaic devices. A wide variety of products can be manufactured with gallium phosphide wafer.
What Wafers are Used for THz Applications?
A scientists requested the following:
"I need FRHZ Si 0.5mm and 1 mm thick with 50 mm diameter. for THz applications. need to block plasma and allow only the THz radiation. Can you please send the quotation."
UniversityWafer, Inc. Quoted:
We have GaP wafers for THz application.
Please reference #266760 for pricing
We have a large selection of Gallium Phoshide Wafers in Stock. Below are some of the specs
Great for low cost light emitting diodes (LEDs). In addition, the brilliance of the bands is enhanced if the device is viewed through an ultraviolet (UV) light source. Hence, this compound presents great advantages when used for solar cells and energy conversion.
| Item | Qty | Type/Dop | Ori | Dia (mm) | Thck (μm) | Pol | Res Ωcm | Nc a/cm3 | Mobil cm2/Vs | EPD /cm2 |
|---|---|---|---|---|---|---|---|---|---|---|
Undoped Gallium Phosphide |
||||||||||
| 5229 | 10 | undoped |
[100] | 2" | 350 | P/P | n-type 0.104 | <4E16 | >141 | <1E5 |
| EJ Flats; Epi Ready | ||||||||||
| G543 | 1 | undoped | [110] ±0.5° | 5×6mm | 400 | P/P | n-type >0.9 | <5E16 | 140 | <4.7E4 |
| Ohmic Contacts on the 0.4x6mm edges | ||||||||||
| 4898 | 2 | undoped | [111B] ±0.5° | 2" | 400 | P/E | n-type 240 | 1.6E14 | 160 | <5E4 |
| EJ Flats, Epi Ready | ||||||||||
N-Type Gallium Phosphide: Sulfer Doped |
||||||||||
| 5161 | 2 | n-type : Sulfer Doped |
[100-10° towards[110]] ±1° | 2" | 302 | P/E | 0.115 | 4.75E17 | 115 | <8E4 |
| EJ Flats; Epi Ready | ||||||||||
| 4348 | 1 | n-type: S | [100-6° towards[111]] ±1° | 2" | 400 | P/E | 0.058 | 9.9E17 | 107 | <5.3E4 |
| SEMI Flats; Epi Ready | ||||||||||
| 5170 | 1 | n-type:S | [111A] ±0.5° | 2" | 350 | P/E | 0.043 | 1.8E18 | 81 | <1E5 |
| SEMI Flats; Epi Ready | ||||||||||
P-type Gallium Phosphide : Zinc (Zn) |
||||||||||
| 5034 | 1 | p-type(Zn) |
[100] | 2" | 400 | P/E | 0.164 | 5.5E17 | 69 | <5.3E4 |
| SEMI Flats; Epi Ready, Wafers have small edge chips near PF | ||||||||||
| 4324 | 1 | p-type:Zn | [111B] ±0.5° | 2" | 350 | P/E | 0.34 | 2.4E17 | 75 | <5E4 |
| SEMI Flats (PF@[110], SF@[112]), Epi Ready, Wafer unsealed | ||||||||||
Cadmium-Doped Gallium Phosphide |
||||||||||
| 99B | 15 | p-type:Cd | [100] | 2" | 400 | C/C | 2.2 | 2.5E16 | 120 | <8E4 |
| P/E or P/P, SEMI/EJ Flats, to be polished, MOQ=5 wafer | ||||||||||
| 99A | 1 | p-type:Cd | [100] | 2" | 400 | P/E | 2.0 | 2.5E16 | 120 | <8E4 |
| SEMI Flats; Epi Ready, doped with Cadium; More such wafers can be made | ||||||||||
Chromium Doped Gallium Phosphide |
||||||||||
| 178 | 7 | SI :Cr | [100] | 2" | 400 | P/E | 2E10 | 4.1E6 | 75 | <5E4 |
| US Flats; Black spots on surface | ||||||||||
| 219A | 1 | undoped | [100] | 3" | 400 | P/P | n-type 0.21-0.29 | (1.5-2.3)E17 | 128-140 | <2E5 |
| SEMI Flats; Chips at edge | ||||||||||
| 261 | 4 | undoped | [100] | 2" | 450 | P/E | n-type >34 | <1.21E15 | 60-140 | <5E4 |
| SEMI Flats; Bubbles near edge | ||||||||||
| 358A | 10 | undoped | [100] | 2" | 400 | P/E | n-type >1E12 | <1E4 | <50 | |
| Semi-Insulating, Compensated material | ||||||||||
| 347A | 1 | undoped | [100] | 2" | 300 | P/P | n-type 1.4E8 | 2.9E8 | 150 | <5E4 |
| EJ Flats; Edge Chips at Secondary Flat | ||||||||||
| 287A | 13 | undoped | [100] | 2" | 450 | C/C | n-type 1E7 | 4E9 | 161 | <5.3E4 |
| P/E or P/P, SEMI/EJ Flats, to be polished, MOQ=5 wafers | ||||||||||
| 112 | 1 | undoped | [100] | 2" | 600 | P/P | n-type 2.15 | 1.6E16 | 170 | <6.2E4 |
| Epi Ready; Back-side has micro-scratches | ||||||||||
| 249 | 2 | undoped | [100] | 2" | 1,000 | P/P | n-type 0.24 | 2E17 | 130 | <8E4 |
| EJ Flats, Epi Ready | ||||||||||
| 249B | 1 | undoped | [100] | 2" | 5,000 | C/C | n-type 0.17-0.24 | (2-3.2)E17 | 119-130 | <8E4 |
| Unpolished | ||||||||||
| 170A | 1 | undoped | [110] ±0.5° | 2" | 250 | P/E | n-type 0.94-320.00 | (3.7-560)E14 | 134-164 | |
| Epi Ready | ||||||||||
| 337 | 8 | undoped | [111B] ±0.5° | 2" | 400 | P/E | n-type >240 | <1.6E14 | 150-160 | <8E4 |
| 111A/111B, SEMI/EJ Flats, P/E or P/P, to be polished, MOQ=5 wafers | ||||||||||
| 166 | 9 | undoped | [111B] ±0.5° | 2" | 400 | C/C | n-type >0.35 | <1E17 | >140 | <5E4 |
| 111A/111B, SEMI/EJ Flats, P/E or P/P, to be polished, MOQ=5 wafers | ||||||||||
| 166A | 4 | undoped | [111B] ±0.5° | 2" | 400 | P/E | n-type >0.35 | <1E17 | >140 | <5E4 |
| EJ Flats; Epi Ready | ||||||||||
| 337B | 1 | undoped | [111B] ±0.5° | 2" | 400 | P/E | n-type 160 | 1.6E14 | 160 | <5E4 |
| EJ Flats, TEST grade - 6mm scratch 5mm from edge | ||||||||||
| 252A | 1 | undoped | [111B] | 2" | 400 | P/E | n-type 86 | 4E14 | 180 | <6E4 |
| EJ Flats, Minor defects on the edge | ||||||||||
| 349 | 9 | undoped | [111B] ±0.5° | 2" | 400 | C/C | n-type 2.3-3.2 | (1.2-1.6)E16 | 165 | <5E4 |
| 111A/111B, SEMI/EJ Flats, P/E or P/P, to be polished, MOQ=5 wafers | ||||||||||
| 88C | 1 | n-type:S | [100-2° towards[111]] ±0.5° | 2" | 400 | P/E | 0.20 | 2.9E17 | 110 | <2E5 |
| SEMI Flats; TEST grade - 0.3mm chip on edge | ||||||||||
| 88D | 1 | n-type:S | [100-2° towards[111]] ±0.5° | 2" | 400 | P/E | 0.20 | 2.9E17 | 110 | <2E5 |
| SEMI Flats; Epi Ready, with edge chip ~0.3mm | ||||||||||
| 296 | 3 | n-type:S | [100-10° towards[110]] ±1° | 2" | 302 ±20 | P/E | 0.115 | 4.75E17 | 115 | <8E4 |
| EJ Flats; Epi Ready | ||||||||||
| 280 | 2 | n-type :S | [100-10° towards[110]] ±1° | 2" | 302 ±20 | P/E | 0.11 | 4.79E17 | 112 | <5.5E4 |
| EJ Flats; Epi Ready | ||||||||||
| 268 | 2 | n-type:S | [100-10° towards[110]] ±1° | 2" | 302 | P/E | 0.11 | 5.3E17 | 105 | <8.9E4 |
| EJ Flats; Epi Ready | ||||||||||
| 304 | 3 | n-type GaP:S | [100] | 2" | 350 | P/E | 0.065 | 8.9E17 | 107 | <6E4 |
| US Flats; Epi Ready | ||||||||||
| 304B | 1 | n-type:S | [100] | 2" | 350 | P/E | 0.065 | 8.9E17 | 107 | <6E4 |
| US Flats, Epi Ready, Scratch on back-side | ||||||||||
| 304D | 11 | n-type:S | [100] | 2" | 680 | C/C | 0.064 | 9.1E17 | 106 | <6E4 |
| SEMI/EJ Flats, P/E or P/P, to be polished, MOQ=5 wafers | ||||||||||
| 304C | 2 | n-type:S | [100] | 2" | 400 | P/P | 0.064 | 9.1E17 | 108 | <6E4 |
| US Flats; Epi Ready | ||||||||||
| 78B | 1 | n-type GaP:S | [100-6° towards[111]] ±1° | 2" | 400 | P/E | 0.058 | 9.9E17 | 107 | <5.3E4 |
| SEMI Flats; Epi Ready | ||||||||||
| 244 | 3 | n-type:S | [100-10° towards[011]] ±1° | 2" | 350 ±10 | P/E | 0.051 | 1.4E18 | 88 | <6.6E4 |
| SEMI Flats; Epi Ready | ||||||||||
| 129A | 3 | n-type:S | [100] | 2" | 400 | P/E | 0.0364 | 1.91E18 | 90 | <7E4 |
| US Flats; Epi Ready | ||||||||||
| 276 | 5 | n-type:S | [100-6° towards[111B]] ±1° | 2" | 400 | P/E | 0.0375 | 2.3E18 | 72 | <5.8E4 |
| EJ Flats; Epi Ready | ||||||||||
| 010C | 2 | n-type:S | [111B-6° towards[1,1,2]] ±1° | 2" | 400 | P/E | 0.140 | 4.1E17 | 107 | <6E4 |
| SEMI Flats; Epi Ready | ||||||||||
| 009 | 3 | n-type:S | [111B] ±0.5° | 2" | 275 | P/E | 0.136 | 4.37E17 | 105 | <5E4 |
| NO Flats; Epi Ready | ||||||||||
| 010A | 2 | n-type:S | [111A-6° towards[112]] ±1° | 2" | 400 | P/E | 0.125 | 4.5E17 | 110 | <6E4 |
| EJ Flats (PF@[1,-1,0], SF@[-1,-1,2]), Epi Ready | ||||||||||
| 012A | 1 | n-type:S | [111B] ±0.5° | 2" | 400 | P/E | 0.10 | 5.9E17 | 104 | <7.8E4 |
| EJ Flats (PF@[-1,1,0], SF@[1,1,-2]), Epi Ready | ||||||||||
| 012B | 1 | n-type:S | [111B] ±0.5° | 2" | 400 | P/E | 0.075 | 8.6E17 | 96 | <7.8E4 |
| EJ Flats (PF@[-1,1,0], SF@[1,1,-2]); Epi Ready | ||||||||||
| 148C | 1 | n-type:S | [111A] ±0.5° | 2" | 350 | P/E | 0.043 | 1.6E18 | 90 | <1.3E5 |
| SEMI Flats; Epi Ready | ||||||||||
| 148D | 1 | n-type:S | [111A] ±0.5° | 2" | 350 | P/E | 0.043 | 1.8E18 | 81 | <1E5 |
| SEMI Flats; Epi Ready | ||||||||||
| 148E | 1 | n-type:S | [111A] ±0.5° | 2" | 350 | P/E | 0.042 | (1.8-2)E18 | 76 | <2E5 |
| US Flats; Epi Ready | ||||||||||
| 148F | 1 | n-type:S | [111B] ±0.5° | 2" | 350 | P/E | 0.042 | (1.8-2)E18 | 76 | <2E5 |
| SEMI Flats; TEST grade, not fully polished | ||||||||||
| 148A | 1 | n-type:S | [111A] ±0.5° | 2" | 350 | P/E | 0.042 | 2E18 | 76 | <2E5 |
| 148B | 1 | n-type:S | [111B] | 2" | 400 | P/P | 0.041 | 2E18 | 72 | <2E5 |
| EJ Flats; TEST grade - Small scratch | ||||||||||
| 242A | 6 | n-type:S | [311] ±0.5° | 2" | 540 | P/E | 0.06 | 1E18 | 100 | <5E4 |
| Epi Ready | ||||||||||
| 284C | 5 | p-type:Zn | [100-6° towards[111A]] ±1° | 2" | 400 | P/E | 0.44 | 2.2E17 | 64 | <5.7E4 |
| SEMI Flats; Epi Ready | ||||||||||
| 284B | 2 | p-type:Zn | [100-2° towards[110]] ±0.5° | 2" | 400 | P/E | 0.43 | 2.4E17 | 61 | <4.7E4 |
| SEMI Flats; Epi Ready | ||||||||||
| 285C | 1 | p-type GaP:Zn | [100] | 2" | 1,000 | P/E | 0.088 | 1.3E18 | 56 | <4E4 |
| 344A | 1 | p-type:Zn | [100] | 2" | 350 | P/E | 0.045-0.053 | (1.8-2.3)E18 | 58-64 | <5E4 |
| SEMI Flats; Epi Ready | ||||||||||
| 344B | 1 | p-type:Zn | [100] | 2" | 350 | P/E | 0.045-0.053 | (1.8-2.3)E18 | 58-64 | <5E4 |
| SEMI Flats; Epi Ready, Back-side poorly lapped | ||||||||||
| 344C | 2 | p-type:Zn | [100] | 2" | 400 | P/E | 0.045-0.053 | (1.8-2.3)E18 | 58-64 | <5E4 |
| SEMI Flats; TEST grade - Back-side scratched | ||||||||||
| 344D | 4 | p-type:Zn | [100] | 2" | 400 | P/E | 0.045-0.053 | (1.8-2.3)E18 | 58-64 | <5E4 |
| SEMI Flats; Epi Ready | ||||||||||
| 328 | 3 | p-type:Zn | [100-6° towards[111B]] ±1° | 2" | 400 | P/E | 0.047 | 2.2E18 | 60 | <5.3E4 |
| SEMI Flats; Epi Ready | ||||||||||
| 319 | 2 | p-type:Zn | [111B] ±0.5° | 2" | 450 | P/E | 0.069-0.074 | (1.3-1.4)E18 | 65-66 | <5E4 |
| SEMI Flats; Epi Ready | ||||||||||
| 319B | 4 | p-type :Zn | [111B] ±0.5° | 2" | 400 | P/P | 0.069-0.074 | (1.3-1.4)E18 | 65-66 | <5E4 |
| SEMI Flats; Epi Ready | ||||||||||
| 246 | 1 | p-type:Zn | [311] ±1° | 2" | 350 ±10 | P/E | 0.11 | 8.7E17 | 68 | <2.5E4 |
| SEMI Flats (PF@[110], SF 90° CCW from PF), Epi Ready | ||||||||||
| 243A | 10 | p-type:Zn | [311] ±0.5° | 2" | 350 | P/E | 0.085 | 1.15E18 | 64 | <2.2E4 |
| SEMI Flats; Epi Ready | ||||||||||
What is Visible-Light-Absorbing Semicondcutor?
Scientists have used Gallium Phosphide (GaP) wafers to research photofunctional construct that Interfaces Molecular Cobalt-Based Catalysts for H2 Production to a visible-light-absorbing semiconductor.
Our research client used the following specs. Reference #225200 for pricing.
Single crystalline (100) GaP wafers
were purchased from University Wafer. The wafers were p-type doped
with Zn, yielding a resistivity of 1.17 × 10-1 Ω·cm, a mobility of 77
cm2 V-1 s-1, and a carrier concentration of 6.95 × 1017 cm-3. Extended
defects result in an etch pit density (EPD) of 4.5 × 104 cm-2.
What Is Light Absorbing Semiconductor?
As the name suggests, a light-absorbing semiconductor has an incredibly high refractive index. This property allows it to efficiently convert solar energy into electrical energy. In photovoltaic applications, light beams are reflected off the surface of the semiconductor, which is then converted into electricity. This process is called photovoltaic conversion. As photovoltaic conversion is a key element in photovoltaic technology, it is crucial to know the properties of light-absorbing materials and how to design them to be highly efficient.
The visible-spectrum range is extremely rich in energy. So, having a semiconductor material that can fully exploit this spectrum would be a real boon to the material world. Unfortunately, most of these materials are expensive and contain toxic elements. To overcome these problems, material scientists from Kyushu University and Tokyo Institute of Technology have worked together to develop a new, cheaper and non-toxic narrow-gap semiconductor material with high potential for photofunctional and light-based applications.
Silicon is an example of a light-absorbing semiconductor material. The band gap of this material is about 1.1 eV, or about 1100 nm. This wavelength promotes an electron from the valence band to the conduction one. This wavelength of light is too low for human vision. However, the band gap of this material allows it to absorb much higher-energy wavelengths, which correspond to the energy difference between the valence and conduction bands.