N-Type dopants

Tyndalization Tyndall scattering Type 4340 alloy steel n-Type dopants p-Type doping... 

Instead of depending on the thermally generated carriers just described (intrinsic conduction), it is also possible to deUberately incorporate various impurity atoms into the sihcon lattice that ionize at relatively low temperatures and provide either free holes or electrons. In particular. Group 13 (IIIA) elements n-type dopants) supply electrons and Group 15 (VA) elements (p-type dopants) supply holes. Over the normal doping range, one impurity atom supphes one hole or one electron. Of these elements, boron (p-type), and phosphoms, arsenic, and antimony (n-type) are most commonly used. When... 

At the same time, it was demonstrated that hydrogen neutralization of dopant impurities also occurs in compound semiconductors. This was first achieved with n-type dopants in GaAs (Chevallier etal., 1985) and then with p-type dopants in GaAs (Johnson et al., 1986b). 

The passivation of n-type dopants in Si was reported by Johnson et al. (1986) several years after it was well recognized that deep defects and shallow acceptors were passivated following exposure to an H2 plasma. Donor passivation effects had been missed by previous workers presumably because the in-diffusion of H into heavily n-doped Si is impeded when compared to undoped or p-type material. 

Kim SM, Jang JH, Kim KK et al (2009) Reduction-controlled viologen in bisolvent as an environmentally stable n-type dopant for carbon nanotubes. J Am Chem Soc 131 327-331... 

Antimony-doped SnOi films were deposited by adding SbCls to the deposition solution. Sb is a well-known n-type dopant used to increase the conductivity of SnOi films. The Sb concentration in the films increased hnearly with that in the deposition solution and was somewhat less than the solution concentration (e.g., 6% Sb in solution gave ca. 4% in the film). The Sb doping increased both the visible/near-lR transmission and mid-lR reflectance of the films, compared to the undoped films. These spectra are similar to those for doped ZnO (Fig. 7.3), and the effect of doping can be explained in the same way. The bandgap increased to 4.1 eV, compared to 3.56 eV for the undoped film, explained through band filhng by free electrons. 

In retrospect, we also explain as being due to the formation of n-n+ junctions the improvement in the conversion efficiency of solar cells made with hot-pressed, polycrystalline n-CdSe upon diffusion of cadmium metal, and n-type dopant, into the boundaries.43... 

In a second embodiment the strip detectors A to H are mounted on an intrinsic p-type silicon substrate 3A covered by a silicon oxide layer 3B. A patterned arrangement of conductor tracks 21 is formed in the semiconductor base 3B. Each track is formed by diffusion or ion-implantation of an n-type dopant material, and isolated from adjacent tracks by means of a channel stop network 23. Bridging links of nichrome-gold are formed to define and connect the read-out regions to the tracks 21. The links 25 are paired and thus provide voltage detection contacts. The tracks 21 are connected to connection pads 29. Signal processing circuitry is incorporated in the semiconductor base layer 3B. 

The impurities Si and Ge are commonly used n-type dopants in III-V semiconductors. Nakamura et al reported that Si and to a lesser extent Ge are suitable n-type dopants in GaN [1]. For Si-doped GaN films, a dopant carrier concentration as high as 2 x 1019 cm 3 was obtained. Similarly, Ge-doped GaN films with carrier concentrations as high as 1 x 1019 cm"3 were reported. The surfaces of the doped layers were found to be smooth and specular, except for n > 1 x 1019 cm 3 when the films became increasingly rough. 

Dopants that donate electrons are termed donors or n-type dopants (e.g. phosphorus atoms in sihcon), since the negatively charged electrons become the majority carrier. By comparison, impurities that accept electrons (boron atoms in silicon), creating holes, ate termed acceptors or p-type dopants, since the positively charged holes become the... 

Interstitial atoms and crystal defects can also behave as dopants. This type of doping is important for n-type CdS. Typical growth conditions for CdS yield S vacancies in the lattice, and the excess Cd then acts as an n-type dopant. For this reason, no p-type CdS has yet been prepared. CdSe and CdTe, however, have been grown in p-type forms, because they can be obtained in more defect-free crystalline phases and thus doping is more effective in controlling the carrier concentration of these purer sohds. 

Nb, 1% C 58-75%, S 70-70% Nb concentrates at the surface, where defects are generated. Nb acts as an n-type dopant development of a more oxidized surface [199]... 

Doping with other elements such as Ge and P (n-type dopant) also results in etch rate reduction but at higher concentrations than B as shown in Fig. 7.30. ° It has been reported that ion implantation of species such as As to a level of lO Vcm reduces the etch rate. On the other hand, doping with As, P, and Sb was found to change little from 10 to 10 /cm in 23.4% KOH + 13.3% IPA. ° Carbon implantation to concentrations greater than 10 /cm causes drastic etch rate reduction as shown in Fig. 7.30. The effect is more pronounced in EDP than in KOH. 

GaP has a number of potential shallow-level donors (n-type dopant). These include sulfur (substituted for... 

C-SiC is the sole cubic polytype among the many SiC polytypes. It has the highest electron mobility of the SiC polytypes. Its band structure is indirect. Most of the commercial applications of SiC are with 4H-SiC and 6HSiC. 3C-SiC has a potential shallow-level donor (n-type dopant) with nitrogen (activation energy of 0.06-0. leV). 

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